Well my mechanic said replacing the calipers is not something you do in pairs so I replaced my only seized caliper and everything is fine, other old caliper still holding up touch wood and until it gives up im leaving it, admittidly i was going though a bit of a rough patch my finances at the time, but im glad i didnt because a year later its still fine. My brakes are already loads better from just replacing one caliper too! so if you did all four i reckon it would perform to your expectations. Ide agree with noby, get some nice grooved discs, performance pads and paint the calipers and they will look the biz. The brakes on the IS200 are overkill already imo, not complaining of course, the car is over engineered in many ways but at the end of the day its a small car with a small engine, heck my brakes are bigger on my IS200 than my Dads MG ZT-T which is alot bigger and more powerful