Alright so I'm going to lay it all out for you guys.. just recently street tuned my 2012 mustang 3.7 on 93oct, car has CAI and cat delete. Running strong, oil changed was done about 2 months ago has not passed 3,000 miles with Castro Full synthetic. I popped the hood today to check oil and it was pretty dark.. just wondering does tuning your engine affect oil life?