Im new here, and notice that alot of ppl have done some interesting things to there GXP's. but there also seems to be a small selection of aftermarket parts. i just recently bought an 2007 GXP, and wanted to know if anyone here has ever experimented with boring and sleeving. from my understanding the outer diameter of the 5.3 sleeve is roughly the same as a 5.7 sleeve, with in a few hundreths of an inch. Any thoughts? I also have an 88 camaro, and have some extra parts i would like to play with.