I have been building the 10v turbo that came with my 4k for a few months now and I have one question stated above. . the only reason I ask is, there seems to be a debate on which cylinder heads are interchangeable between 2.1 and 2.2 stuff (though I cant really see the reason why) so it had me wondering about my crank dilemma. . . cylinder spacing the same?? how about bearing size? Bentley says the stroke is identical. Its a KH 2.1 that I have already bored out for MC pistons but the crank saw a little bit of abuse and would be cheaper/easier to swap out if I could use a good 2.2 version. what say the real audi community??