I wouldn't want a 6 inch lift of they made them as some off camber trails had me puckered a few times and probably would have rolled it already with a 6 inch lift which raises the center of gravity. It would be alright if you were cruising the swamps on flat lands.....or for looks.
You can fit 35's with a BMC,creative caster settings and plastic trimming now if you don't actually wheel it and stuff the tires . Mall crawling or for looks should be fine though.With 35's you are going to be tearing stuff up in the wheel wells or the tires themselves like I did offroad as our wheel wells are smaller then FJ's . A body lift would solve the problem raising the wheel wells up but opens up other cans of worms .
These are rub marks on the top of my front wheel wells from the tires hitting when stuffed and I'm running KM2 305/70/17's which are actually a little smaller then the 33.9" they claim. I also tore chunks of tire out in the back on the inside edges from hitting the wheel wells.
[MENTION=8206]harper7[/MENTION] is spot on in his comments. I am running a similar tire in a more narrow size. I've spent a lot of time trimming, bending, etc to eliminate rubbing but I've only been able to eliminate the major rubbing and their are scars all over my wheel wells from tire rub. I think that a 33-34"ish tall tire is plenty for the runners. Anything bigger and the rubbing will be the least of your concerns. If you were to go bigger be ready to sacrifice your COG, drivetrain reliability, power, safety, etc.
If you really want to run. 35"+ tires. I'd go with a 1st gen Runner or hilux, American pickup, or a Wrangler.
