One of the biggest differences between the '05-'07 models and the '08-'09 ones are the spark plugs. On the right, the '08 plug has a more traditional plug strap--making it easier for aftermarket companies to reproduce plugs. The plug on the left is the goofy '05-'07 plugs that have an obscure end that has to be crushed in order to re-gap the plug. Only two companies make aftermarket plugs with colder heat ranges for power-adder combos. The end isn't the only difference; the body of it is funky too. We stuck with the stock '08 plugs, which are fine for up to 100 hp worth of nitrous. Anymore than that, Carlson suggests getting one heat range colder than stock. The aftermarket is said to be working on colder plugs, due out by the time you read this issue.