As helpful as this site has been with a wealth of knowledge wheel spec and fitment is not one of those. I have a 94 80 wanting to change wheels to 17 inch. So in my research this site and other lots of confusion . So my plan is fjc 7.5j×17et15 knowing I have 8j×16et14 wheels now. As I see post about offset ,backspacing and the need to use spacers. With the above wheel spec total track width will be reduced by 13mm- 1/2 " and backspacing reduced by a 6mm- 1/4" am I missing something???