I have the stage 1 upgrade and the check engine light came on at around 150 miles. Not sure if this related but I changed the plugs to NGK Iriduims and the light went out not too long afterward. Popping on decel is normal.
John, how difficult was it to change the spark plugs? I may try the Iridiums to solve my check engine light problem.
This may sound like an ignorant question, but how many spark plugs does our motor require? I assume 2, but just want to be sure.
Thanks!