So about 3 months ago i purchased my 06 pontiac grand prix gxp with the 5.3L LS4. Some people have said I should use fully synthetic and others have said conventional motor oil. Right now i believe it just has conventional oil from the dealer ship in it but i was wondering what type of oil and filter yall would recommend for best performance and long engine life. I dont drive it like a maniac as this is my daily driver car. And another thing. Ive put just over 3000 miles on it since i purchased it and the oil life gauge in the car still says it has 60% oil life left?? How many miles should i go between oil changes or should i just go by what the gauge says? Any and all advice is welcomed.