Just to add to the thread, I have recently traded in my 2006 2.5 WRX against an JDM S202 Bugeye and I have not regretted it for one second.
Yes the 2.5 has more torque and after I modified it with a 3" exhaust system with a 100 cell sports cat, Prodrive uprated fuel pump, RCM induction kit, 3 port boost control valve and an STi TMIC and a remap with Bob Rawle it was a much better car about 290bhp/390 lb ft torque but after 6000-6500 rpm it had run out of steam.
But the JDM 2 litre engine in the S202 just is far more enjoyable to drive and the 6 speed gearbox with different ratios to the std 6 speed box is excellent. The JDM engine just revs and pulls really hard and it puts out 320bhp in the S202, although it does not have the torque of the 2.5 it is more of a 'drivers' engine.
If I were using the car everyday then I would have stuck with the 2.5 WRX but as with most other Impreza owners it is a weekend car and it would be the JDM 2.0 engine every time for me now.
