IT seems that virtually every new car these days is getting bigger and more refined than the model it replaces. The new Subaru Impreza WRX STI is no different.

The STI has always been a car with an image. The additional suffix means it is a tuned version of the sporty all-wheel-drive Subaru WRX, which is itself derived from a rally car.

In terms of performance and kit, the STI has always been the outrageous flagship model. But Subaru has tweaked this latest iteration somewhat.

For one, it no longer has a sedan body style but is now a five-door hatchback instead. It still looks menacing enough, with big 18-inch wheel, Brembo brakes and box arches. The wider fenders also mean that the rear doors are different on the STI than on a less-endowed WRX or a more conventional Impreza.

Yet the biggest change is not its shape but its target group. Where once the STI was focused on being the hardcore, no-compromise alternative, it is now a bit more grown-up. The ride is a little softer, and the cabin a little quieter. Where once the old STI's springs were hard enough to jolt the fillings out of your teeth, the new ones - while still being stiff - are more progressive. The overall drive is a lot smoother too.

Don't be mistaken, though: The STI can still take things to the extreme. New to the car is the SI-Drive, or Subaru Intelligent Drive. This knob on the lower centre console offers three driving modes. The first is the I-mode, which reins in the 300 horses available and smooths everything out for a softer and more fuel-efficient drive. The next is the Sports mode, which gives things a harder edge. But it is the Sport Sharp mode which is the most electrifying. Switch to it and the engine rumble turns deeper. The throttle response is heightened and the engine revs the redline at 6,700 rpm in an instant.

Together with the DCCD or Driver's Control Centre Differential buttons below it, they are capable of making the new STI feel almost as raw as the old STI. With the DCCD, the centre differential can be left in auto to handle most road conditions, or manually adjusted to transfer more power to the rear wheels for more dynamic handling.

This is just one of the many features which makes the STI stand out from the cheaper WRX, which is $29,000 less. Another is that the STI's front and rear lower arms of its suspension are made of lightweight aluminium, compared with more 'ordinary' steel.

Most interesting, of course, is its blistering acceleration. Zero to 100 kmh is accomplished in just 5.4 seconds, versus the WRX's time of 6.1 secs.

So is the new and more refined Impreza WRX STI a better car or a sell-out? Sitting in the comfortable alcantara-lined bucket seats and enjoying the smoother ride in the bigger interior, it is difficult not to call them welcome improvements. But by making the new car seem less aggressive than before, it may have disappointed some of its performance-oriented fans.

Subaru Impreza WRX STI

Engine: 2,457cc flat-4 turbocharged
Gearbox: 6-speed manual transmission
Max power: 300 hp @ 6,000 rpm
Max torque: 407 Nm @ 4,000 rpm
0-100 kmh: 5.3 secs
Top speed: 245 kmh
Price: $116,000 (with COE)
Distributor: Motor Image Enterprises, tel 6417-0300