I believe Nay is running 37" tires with 4" lift.
Me, I'm running 35" tires (315's) with zero lift. I only get the occasional rub-kiss on the LF fender under compression--not when flexing, but when hitting a big enough bump at speed.
IMO, 4" lift, with 4" bumpstops = stock up travel. However, all lift springs are stiffer than stock springs, so you should be okay, except on really big hits.
35" tires with zero lift? What size rims?