Im going to keep it simple.

2006 F150 Lariat SCREW 4x4, stock 20s, currently on 35x12.50 Trail grapplers with a 2.5" leveling kit.

What brand of 6" lift could I use to keep my Stock 20s, I like the stockish look I have.

 

Any 6inch lift will enable your truck to use the stock 20inch rims. The lift you choose depends on your budget and which brands you prefer. My 150 is Pro Comp and 250 is Zone.