I have a 07 & 09 m8 that have fouled the plugs from day 1, the 09 being the worst. If I want sleds to perform decently I have to change plugs at 500 miles or less. In the beginning around 250 for the 09. My question has anybody else had this experience ? If so were u able to cure it, other than buying a new sled? I know a lot of people premix and I have considered doing this. The ? is has anyone gone to premixing and seen the life of plugs increase dramatically, to 1500 or even 1000. Or?