Thanks for the feedback. Silkolene makes a semi-synthetic and a full-synthetic. The full syn oil seems to be more of a racing grade. The semi is much cheaper and still meets the specs in the owners manual. I can get a gallon of the semi for $32, but I can bring the jug back and the shop will fill it out of their bulk supply for $20. Turns out I've been using the semi-syn oil for the last part of the summer last year since they changed my oil the last time. I finally purchased a lift so now I can change my own oil.
