Q: Why?
A: any integra type r that is in good condition is an excellent choice. the chassis has extra reinforcements, a great motor, short gearing with LSD, different suspension and brakes, and nice seats. in short, it has been tweaked from the factory for circuit use. the GSR is a great choice as well. not quite as powerful but can have leather, sunroof, and a better stereo. the 'problem' with the type R and GSR trims is that they are sought after by honda enthusiasts and therefore command a high price premium. also, all integras are usually driven hard or modified, so it is very difficult to find a good condition example. in reality, any integra that is free of rust, and has been maintained properly and driven comptentently is the best buy. don't get a beat up type R or GSR, no matter how nice the price seems. if it is too cheap, it is because it will be a money pit in the future