15x8 w/ 4.5” BS on front/good handling size?

It’s big bolt pattern with QA1 upper/lower and Wilwood discs I forget the disc size.
well... that makes it a little trickier. basically, anybody that gives you a rec for what fits on their car with stock suspension you can disregard. or maybe use as a very loose guide.

so you've got the increased track width of the BBP spindle, and i *believe* the wilwood adds some to that as well, with the hub pushing the WMS out even further.

i'd hazard a guess that 3.75 BS isn't going to come near enough to make happen what you want to make happen, unless you're thinking of running a 205.

i hate saying this, but i'd try and find somebody that's got the same set up and see what they're running. from there you could at least make a better educated guess, or have some hard numbers that you could play with.

i usually say 4.25 minimum BS (which is stock) is where you want to start, with more being better. but i think at 5-ish you start to get very close to the tie rod end and possibly the upper ball joint with 15's & 16's so you need to go bigger to clear those and then run more BS and you can tuck in some fat meats.