Been using M1 since my '09 Saab was new and now has 80,000 mi. I see I can easily get RP online from Jegs for under $8 per quart with free shipping-hard deal to beat.
I do about 8-10,000 mi. OCI's and the car is tuned. I know M1 can go over 14,000 mi. without a problem as I did several UOA's.
I...