Ok So I see I am late to the game as it is already 7 pages long, but I am in the same boat as you. Mine wont spin the tires. 285s may have something to do with that, but i have traction bars, and the truck in my sig. Only thing I am worried about is overboosting and lifting a head but still I dont feel like mine has the ability to light them up in 3rd. Maybe i dont beat on it enough!
I will also add my boost numbers for reference. I can cross the 10 psi at 1600-1700 depending on how hard i get on it, or do it closer to 2000+ I tend to try to boost in higher rpms usually 2200+ due to my worry of lifting a head. I also wont push it past 15 psi. I am also intercooled, and 15 psi is stupid easy to get to. Half throttle acceleration, 3 4 or 5 gears and I am pretty much sitting at 15 psi. that is also where i back out.
Boost pressure also is very dependent on engine load. If you hammer down at 1200 rpms you could be boosting 5+ psi (for a split second) vs my cruising boost of 3 psi at 2100 rpms.