if you are talking about the cam timing i have done it (link does not work for me). you cannot go more than +/- 5 degrees otherwise the ecu will see this (via cam, crank sensors) and de-tune the engine, put the redline at 4500rpm. if you go less, say +/- 3 degrees it is pointless. all you are doing is moving the powerband either lower in the revs, or higher. no real gain, the best setting is the factory setting. search it in the forum here, i did a good writeup on the subject a couple of years ago.