I have now owned this car for 2 years and it has been a dream to own. Has had no major mechanical issues with the car and it is massive fun to drive. I can honestly say that for the money you will be very hard pushed to find anything this quick.
The performance of the car is something else. The acceleration from the 280 Bhp 2.0 liter turbo engine is really quite astonishing, with mid-high 4 second 0-60 times quoted, which is largely thanks to the close ratio Group N gearbox. The downside of this though is that top speed is limited to 118 Mph (de-restricted) but since I don't really get close to that on the mountain roads of Japan, where handling and acceleration are more important, that is not really an issue.
The Type RA's are also lighter than the standard STi's which does aid handling and acceleration, though the Ltd version that I own does come with all the electric goodies found on the normal STi so the weight gains are compromised a little, but the car still comes in with a weight saving over the V5/6 STi.
This car is also equipped with the DCCD which is a controllable center differential that allows you to control the torque split between the front and rear wheels to an extent. With more power sent to the rear in fully open mode, the car can be a lot of fun, especially in the wet.
The handling generally feels a lot more dynamic than my previous car (WRX wagon with Tein Super Street coil overs, uprated ARB's and front/rear strut braces) and the grip is astonishing. However the understeer, common to all Impreza's, is still present on this model, but can be dialed out to a large extent by using the DCCD and adjusting your driving style to suit.
Downsides with this car are mainly the noise and the harsh ride. The car has less sound proofing than standard models, so the engine, road noise and rattles and squeaks are much more noticeable. The ride is necessarily harsh as the STi suspension is quite stiff, but on long drives it can become quite uncomfortable, and as this is my daily driver, I do occasionally do long stretches on the highway.
Also of course, running costs are high. Servicing is every 3 months when I do a full engine oil and filter change. All other fluids, fuel filter, plugs and leads are changed once a year. This is purely down to me, but it is worth it in the long run as the car has been trouble free since I have owned it. Oh, and insurance costs can also be very high.
Finally, as an indication of how good this car is, I was intending to get an Evo 6 as a replacement for the WRX and on a whim test drove an RA, and in my opinion it was simply a better, more involved driving experience and felt quicker. The cars were about the same price to buy (about 1.5 million yen on average for a good example) but for me there was no contest. The car really is that good.