I use Mobil 1 5w30 full synthetic "high mileage" - I change it every 7,500 miles or so, usually has 40-50% on the OLM. I could go longer but I never have, earlier on I changed it religiously @ 5,000 miles.
Could I go longer? Sure. But I for one am convinced a more rigorous oil change interval is essential to avoiding any of the "lifter failures" people are experiencing w/ these cars. Thin old oil could be the culprit.
You can agree or disagree, but I'm the one w/ 102,000 miles on the car and not one tick
of a problem
'08 GT sport/premium, tints 20/35, 18" TSW nogaros w/ bridgestone blizzak winter, 19" sport oem w/ hankook evo summer, Philips crystalvision bulbs, debadged, Vararam OTR, JBA 1-3/4" LT's, ported TB, MF axlebacks, MF X-pipe, DBA-powerslot brakes, russel SS lines, hawk ceramic pads, GXP shocks/struts, lovells poly strut mounts, Slowhawk Tuned 344/356
Gone -'04 GTO A4 2.5" custom exhaust, sweet thunder muffs, H pipe, Z06 heads, Baer brake it, 20% tints, torrid red, AEM brute force intake, tuned