I did make the stairs w/o wheelspin and I have a 99 Acura SLX. I used 245/70/16 BFG ATko on stock rims and tokico trekmaster shocks. I aired down to 20 psi and set my LSD with the handbrake before climbing. I used a bump start at the bottom and had to re apply the handbrake a few times on the way up to insure traction. My vehicle is almost completely stock. Wheel placement is critical on the ascent. You have to have a mental image of your wheels in relation to the terrain. It IS a white knuckle exercise. Thanks to Terry Johnson for the driving instruction.