I am installing a 4" superlift on my PU and the kit calls for a 33x12.50 on 8 inch wheel with 3.75 inch backspace. I really like the Dick Cepek DC-1 but they only come in 15x8 w/ 3.65 inch back space or 16x8 with 4.03 inch back space. If I understand back spacing correctly, the 3.65 will mke the tire stick out past the fender more than the 4.03. That being the case, i'd rather go with the 4.03 but will it fit without rubbing anything like knuckles, etc?

 

You got that backwards. Here's a thread that will tell you more about what rubbing issues there is.

https://www.yotatech.com/forums/f120/toyota-faq-66255/