Im trying to order a lift but can't figure out what will work. Is anyone running a 5" to 8" lift on there 2015 duramax and up with the stock 20" wheels. I'm wanting to run a lift and 37x12.50r20 toyo on the factory 20" wheels and trying to find out if they will fit and fit with or without spacers. If I do need spacers, what size?