Last night I spent about 2-3 hours reading over the forum after doing several searches. My intent is to improve what I have been doing, but since I have daily drivers I am not looking to go way over board. If anyone would care to respond I would be grateful. I have a 2001 Jetta with a VR6 (20K miles) and a 2001 GMC C3 with a 6.0L (15K miles). I do my own oil changes and started at about 500 miles on each one using Valvoline full syn. I did changes at 1K and 3K also and lately have been doing a 5K interval. They may see a couple of 20 degree days a year if I go up skiing (otherwise it is a garage in the 40's.) The truck spends some time in the summer pulling my 3500lb ski boat with temps never exceeding 100 degrees. After reading over the forums I have decided to change brands. I do not desire to get into oil sampling (although I have always been curious about my engines.) I wish to continue with my 5k oil changes (which is just 2x/yr) and despite some added cost, I will definitely run a full synthetic. Which commonly available synthetic would be correct for my application?