I have a 06 Lariat 4x4 Screw and am planning on putting on a Fabtech 6" lift kit that comes with the Bilstein struts and Performance shocks. I am wanting to put 35x12.5R20 tires on it. I was thinking about getting the 20x10 with a -12 offset. The website says 5" BS but with -12 offset that should be about a 4.73" BS I believe. How far will that wheel stick out of the wheel well. Can I expect some trimming of the wheel well? If anyone has 20's on a Fabtech 6" lift how wide is your wheel and backspacing???

 

I have 17x9s with 4.75" backspacing and 35x12.50 mud grapplers. I had to cut the bottom corner off the plastic part on the bottom of the front bumper. Nothing off the back side of the wheel well or fender.
Here's what mine looked like with the stock bumper:



And here's what it looks like now:

 

I saw your truck when I searched a few threads. That things a beast. I was going to stay with 18's (thats whats on my truck now from the factory) but my wife actually wants me to get the 20's. She said I might as well get the "big" ones. I'm just afraid if I get the 20x10's with the 5" BS I'll have to cut.

 

It's probably going to come down to what tire you run. Guys with a more street friendly tire don't usually need to cut, but if you have a tire with big lugs like the mud grappler then that will make it more prone to rub. Either way, if you have to cut a little it's no big deal. It's scary at first, but if you trim little by little you won't mess up.

 

Any trimming required will be very minor at most. You won't have to cut any of the body, only a little plastic on the front bumper if any at all. And I would try to talk your wife out of 20s. Your wallet will be more angry at you for buying 20" rims and 35s for 20s than your wife will be for getting 18s

 

As stated above, only trimming that may be needed is on the lower front valance. And I say go with the 20's. 18's are just to small. The smaller the wheel the more congested the wheel looks.