When I first got the car I'd have it changed every 3,000-3,500 until it had about 20,000, now I go 5-7,000 miles always use 5w30 and Fram extended guard
Unless you drive like a complete a-hole the engine should go 150,000 before it drops any power or gives any issues as long as you change the oil regularly...may start burning oil as the mileage gets up there (mine hasn't yet w/ 68,000), and you would probably want to change spark plugs @ 100,000...but I seriously see no reason the engine/tranny combo can't go 150k w/o ANY issues.
I think a big reason I have no lifter tick or issues w/ the DOD parts etc. is because I have always used synthetic and have been religious about not letting it go too long. Those parts are @ the top of the engine and would be the first to start suffering if the oil was losing its viscosity, I also think higher than needed revs are a killer for the LSx engines....I plan on hitting 120-140,000 before I even think about selling it
'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