Without reading all the other post or asking you for specifics I know what the cons were. If your motor didn't have it from day one or right after it was broke in you would get leaks right? I've heard this a MILLION times, BS I tell you. Before I had the CSVT I had a 93 Park Avenue Ultra that I bought w/ 84K and switched to Mobil 1 right away...no leaks! Before that I had an 89 LeSabre T type that I bought w/80K and ran Mobil 1...no leaks again! Also during the time of owning those 2 Buicks I had a toy, which was also a Buick...1987 GN which I ran Mobil 1 in and that car had 87K on it when I first got it. The only leak that car had was a rear main seal and if you know anything about 3.8 SFI Turbo motors they ALL leaked, especially when you run between 18-22 psi of boost through them
In closing I say run the Mobil 1, in your weight (unless its real cold where you live, then run the 0w30 in the winter monthes) and be done with it. Oh yeah, don't forget the Mobil 1 synthetic oil filter too
