Another new Acura model went on sale two years ago: the TSX -- an under-$28,000 sport sedan cheaper than any cars sold by Acura's Japanese luxury-car competitors. It isn't really a new car, though; it's a version of the smaller Honda Accord sedan that is sold in Europe, and comes only with a four-cylinder engine.

For 2006, however, it gets a bit more power -- up to 205 horsepower from last year's 200. And there are some exterior enhancements, including a new grille, hood, side sills, wheels, headlights and taillights.

It's a popular car with Acura fans even though it has less power than lower-priced mass-market sedans, such as the V-6 versions of the Honda Accord, Nissan Altima and Toyota Camry.

And rather than introduce a higher-price model to fill the larger void between the RL and the more expensive Lexus and Infiniti high-end sedans, Acura chose to roll out the TSX into the narrow space between the RSX coupe and the TL sedan.

Now that Acura has plans to discontinue the RSX, the fate of the TSX remains somewhat in doubt. Honda for years has wanted to move the Acura brand up scale to match Toyota's Lexus brand. To that end, the company has said that it really doesn't want any affordable cars in the lineup -- that is, cars that sell for under $30,000.

The automaker had planned to drop its entry-level Integra model earlier this decade and not replace it with a similarly priced coupe, but dealers protested. Acura responded by replacing the Integra with the RSX, slightly more expensive but still quite affordable at a starting price of $20,325 for the base model with a 160-horsepower engine.

The TSX starts at $27,890 with either a six-speed manual or five-speed automatic transmission. That's $4,135 more than the most-expensive RSX, the 200-horsepower S model.

With the only available option -- the GPS navigation system -- the TSX tops out at $29,890, which, with the freight charge added, puts the TSX just over $30,000. That price might be high enough to save the TSX from the same fate as the cheaper RSX.

But I feel sorry for all the regular folks who no longer will be able to buy a new Acura product such as the RSX for a price that rings up as quite a bargain.

As the entry-level sedan in the Acura lineup, though, the TSX is still quite a bargain itself, considering all that you get for the money.

This nice-looking sport sedan combines a responsive engine with drive-by-wire throttle control system -- which has no direct mechanical link between the accelerator pedal and the engine -- and what Acura calls a "race-bred suspension."

Along with the very refined interior and lots of practical new technology, the TSX offers the consumer a comprehensive package at a price well below that of some comparable European sport sedans.

The interior is quite sporty, with modern LED instruments and well-placed and designed controls. The front sport bucket seats are among the best in their class, and even the rear seat is comfortable for at least two adults, although it can hold up to three.

Standard luxury amenities include perforated leather seats; leather-wrapped, three-spoke sport steering wheel with audio and cruise control switches; dual-zone automatic climate control; power moon roof; 360-watt Acura eight-speaker premium sound system with six-disc in-dash CD changer; power windows and door locks, and keyless entry.

The double-overhead-cam engine uses Honda's i-VTEC variable-valve-timing system. It is an aluminum alloy engine that produces 164 foot-pounds of torque. EPA fuel-economy ratings are 21 miles per gallon in the city and 29 highway with the manual gearbox, and 22 city/31 highway for automatic models.

High-tech features of the TSX include the drive-by-wire throttle system; programmed fuel injection; Vehicle Stability Assist with traction control; and a low-emission exhaust system.

Acura says the increase in horsepower came partially as the result of enlargement of the engine's throttle body and intake duct to increase air flow from 95 liters per second to 110. Also, the company said, the diameter and shape of the intake valves were changed to increase intake flow by 16 percent.

There is also a larger-diameter exhaust pipe for 2006, along with reductions in silencer and catalyst resistance, which increased overall exhaust flow by 9 percent to 125 liters per second.

The TSX comes with platinum-tipped spark plugs and a self-adjusting cam chain that are designed to allow the engine to go 100,000 miles between tune-ups.

For performance addicts, the six-speed gearbox is the natural choice. Acura says it has short shift throws as well as synchronizers on all gears for quick shifting. The unusually light case -- 6.6 pounds less than the weight of a comparably sized aluminum transmission case -- is made from magnesium alloy, which is often used in race cars.

Despite its light weight, it is "extremely rigid to damp out noise and vibration," the company said.

Our test car came with the automatic transmission, which includes a sequential sport-shift function that allows the driver to change gears manually without having to use a clutch. One of the reasons enthusiasts like this car is its sports car-like handling, which Acura attributes to the car's rigid unibody construction and "race-bred" four-wheel-independent double-wishbone suspension.

"The suspension is track-tuned to reduce lift, dive and body roll and boasts gas-pressurized shock absorbers and large front and rear stabilizer bars," Acura said.

Also standard is variable-assist rack-and-pinion power steering, which changes the amount of help it gives the driver according to the vehicle's speed. The higher the speed, the less power assist, giving the driver more of a feel for the road, especially in tight high-speed turns.

This car has some of the best brakes I've experienced on a street vehicle. Disc brakes are standard on all four wheels, and the antilock system with electronic brakeforce distribution are included.

Among the tweaks to the TSX exterior design for 2006 are a new front bumper, a redesigned grille and fog lights that are built into the bumper. Also new are the side sills and nine-spoke alloy wheels.

Changes to the rear include a more-sloped rear window, along with revised taillights and bumper.

A Bluetooth hands-free phone system is standard, just as it is in the TSX's bigger siblings, the TL and RL sedans. The system can handle up to six different phones, and has its own 50-number phone book.

Four new exterior colors are available this year: alabaster silver metallic, glacier blue metallic (included on our test car), deep green pearl, and royal blue pearl. Carryover colors are premium white pearl, nighthawk black pearl, arctic blue metallic, Milano red and carbon gray pearl.

The audio system now has standard XM Satellite Radio, along with an auxiliary jack in the center console for connecting an iPod or other digital music player.

The eight-way power driver's seat has a new two-position memory, and a four-way power passenger seat is new this year.

The optional navigation system has voice recognition and an expanded memory and faster processor. Included in the system's DVD database is the Zagat restaurant guide. Seat-mounted side air bags are standard for the front occupants, as are side-curtain air bags for front and rear passengers.

G. Chambers Williams III is staff automotive columnist for the San Antonio Express-News and former transportation writer for the Star-Telegram. His automotive columns have appeared regularly in the Star-Telegram since 1995. Contact him at (210) 250-3236; chambers@star-telegram.com.

At a Glance: 2006 Acura TSX sport sedan

The package: Compact, front-drive, five-passenger, inline four-cylinder powered entry-level premium sport sedan.
Highlights: This car was all new two years ago, and is the lowest-priced Acura sedan. It has more power and some exterior design tweaks for 2006.
Negatives: No larger engine is available for those who want more power; high-compression engine requires premium fuel.
Engine: 2.4 liter inline four-cylinder.
Transmission: Five-speed automatic, six-speed manual (no price difference).
Power/torque: 205 horsepower/164 foot-pounds.
Brakes, front/rear: Disc/disc, antilock.
Length: 183.3 inches.
Curb weight: 3,257-3,356 pounds.
Trunk volume: 13.2 cubic feet (12.8 with navigation system).
Fuel capacity/type: 17.1 gallons/premium unleaded.
EPA fuel economy: 21 miles per gallon city/30 highway (manual); 22 city/31 highway (automatic).
Major competitors: Audi A4, Mercedes-Benz C230, Infiniti G35, Lexus IS 250, Cadillac CTS, Volkswagen Passat, Nissan Maxima, BMW 325i, Jaguar X-type, Saab 9-3.
Base price range: $27,890-$29,890 plus $615 freight.
Price as tested: $30,505 including nav system ($2,000) and freight.
On the Road rating: **** (four stars out of five).

Prices shown are manufacturer's suggested retail; actual selling price may vary according to manufacturer and/or dealer rebates, discounts and incentives, if any.