I just talked to Coz and for 50 bucks a can get a set of NGK colder plugs for my max. Stock are #4 and they have #5 and #6. I want to eventually run up to a 100 shot maybe 75 so how cold should i get the plugs??

for every 100 hp over stock, you go one heat range colder. (stock is #4 range?? if so, you want a #5. A #6 will foul quickly when you're not on the juice.)