damn, the hardest part for me was removing and reinstalling the passanger side studs off the header. the timing wasn't that bad at all. i can really feel the difference @ the upper end of the rpms, and of course w/ 4 cats hallowed out it sounds pretty sick. I was wondering if there's a 'break in' period with the swap, i havent gunned it all the way yet. and yeah i found out why i was getting the check engine flag with an O2 sensor... i found that the wires were torn apart near ther oil pan :| i got robbed by my local dealer for $240 in new sensors cause they told me they were bad and they didnt check the connections.