I had 33x10.5x15's BFG Muds on stock rims on my 1990 LS (now has 32x11.5x15's BFG AT's) Torsion bars moderately cranked- No issues with tire size. I also now have 1995 SR and it has 31x10.5x15's Dayton Timberline AT's- Don't know who makes them but appear to be nice AT tire. 33x10.5x15's make monteros look awesome- but are costly.

my personal general rule is to not trust anything someone says there, my wife worked there and she knows what I'm talking about, cause they aren't hired for experience just hours one can work.

I've gotten the 3 plus 1 free at Pep Boys, for their brand AT tire (Definity?) in a 30x9.50-15 that I ran on a '98 GMC Sonoma with a 2" body lift (youngest daughter now drives it). Also got the 3+1 deal from Firestone on their Destination AT, 31x10.50-15, for a Jeep Comanche truck I used to have. Both tires were a good deal at the time, MUCH less expensive than a BFG AT. I'm running Sumitomo ATs on my Monty (265/70 on 16x7 Tacoma steelies), and they don't stick out at all, give a good quiet ride, and perform well in the snow and slush. I was in Wally World last week, and couldn't believe how much tires have gone up in price. They carry a Goodyear Liberator AT that looks to be an awesome tire, but they want about $185 for a 31x10.50-15, plus mounting, balancing, valve stem, and tire disposal (add another $15).

If you have a Treadquarters / Merchant's Tire / Kramer Tire / Firestone / Pep Boys near you, I'd check 'em out for prices. 'Course you could also look on Craig's List, which is where I found my Tacoma steelies.

If you're still looking for tires, discounttiredirect has 31x10.50x15 Falkens for $109 each with free shipping. Even with a mount from somewhere else, you should get away for under $500.