OK, I drive a 99 Pontiac Grand Am GT 3.4L V6. I have run Mobil 1 synthetic in her until now, about 50,000 miles, with 3,000 mile changes. The stuff is too expensive for me, so I switched to regular Valvoline All Climate 10W-30 for the summer. It's starting to get cold where I live now (Colo. Spgs. CO). I come here and see all this negative stuff about conventional Valvoline oil and about 5w-30 oil, which I'm about to run to help combat the colder temps at startup. I am totally clueless now as to what I should use!!!!!! You hear one thing, then someone says another. What would be your recomendation, with supporting proof, as to the best over the counter conventional oil? I just don't want to continue spending 4 times the money for synthetic when many people say premium conventional oil is fine. Also, is 5w-30 OK for colder temperatures? I always use 10W-30 in the summer time. One more thing, oil filters. Are regular ultraguard AC Delco's fine (not the ultragaurd gold or silver)? Thanks very much for anyone's input on such a confusing subject!