Any 92-01 GS-R header will bolt to the engine. The 92-93 is going to fit a wee better, because the B17A is based off the B16A block so the header won't stick down the extra 9 or so millimeters that using a 94-01 B18C header (based off the B18A block) would. You'll never notice a difference if you used a stock manifold, and in the case of the B17A, it is the pobably the exact same stock manifold as your B16A anyway.

Any aftermarket header will require modification to the rest of your exhaust system to allow it to bolt together.