I use Mobil 1 Full synthetic 5W-30 simply because it's not new anymore and wasn't when I got it. If bearing tolerance has anything to do with it, mine have grown with mileage. I've got a little over 71k, so I don't see an issue with using a little bit thicker oil unless the car is brand new, or you're breaking in the engine. It's not like he's trying to throw straight 40HD in or something. I haven't had any problems and usually get 19-20 mpg.
__________________
2002 Mustang GT, 271hp/306tq on 87 CMR Tune, Roush short throw rally style shifter, King Cobra Clutch, Roush CAI, C&L Plenum, BBK/Roush 75mm T/B, Kooks L/Ts w/catted X, Bassani Cat-back, Eibach Pro-kit Springs, Energy Suspension bushings, KYB AGX's, Hotchkis C/C plates, UPR ProStreet rear control arms, Brembo Drilled/Hawk pads, BFG's, Dual Halo Projector 8k HIDs, Kenwood: KDC-X790, KAC-9102D, KAC-8402; Infinity: 6810CS, 6812CF; Orion: P series subs all powered by Optima 
My car http://www.cardomain.com/ride/2628572
My truck http://www.cardomain.com/ride/2206751
|