I have a 95 gt with cai, 70mm TB, mac duals, edlebrock intake and 3.73 gears. The owners manual says regular gas. The guy I bought it from said he used premium. The plugs are light grey (almost white) and 1 plug was coated with an ashy build up (i dont know if the plug issue is related. The car hasnt used any oil since i bought it 1000 km ago. The timing was at 3 degrees. It is at 10 now, I might try a little higher depending on whether I keep running premium and the price of gas, lol. Any thoughts?