Ok, down to the last question. Are you going to be running the BBP Moser axles with BBP brakes (10x2.5") or are you running their BBP axles that still use a SBP flange offset with SBP brakes (10x1.75"). I know, now we're really getting down to it. Makes a difference though, about 5/16" per side. Doesn't sound like much until the tires rub, then it seems like a mile.
Assuming you're going to run the BBP axles and brakes, the 15x10's with 295/50/15's would stick out about a 1/2" further than my tires do. That would basically put them even with the outside lip of the quarter panel. If it were my car, they'd rub like crazy because of my ride height. They'd probably touch just sitting still, it would never work. But, you have two things working in your favor. The 295/50/15's actually have a narrower tread width than my 295/35/18's, even though my tires have a narrower section width. That's because of the curve on the sidewall- my lower profile tires with a short sidewall are more square, the 295/50/15's have a lot more curve on the sidewall, so, you have more room at the top where it would rub. And you're running SS springs. Which means, more than likely, they wouldn't rub. Your ride height will be a couple inches higher than mine, and those springs are quite a bit stiffer. So, it would totally depend on your ride height. What I would say about that combination is that they don't really fit, because they won't fit into the wheel well. But, depending on your ride height, they may not rub at all. If your car sits high enough, it won't be a problem. Lower it and they won't fit.
If you run the Moser's with SBP brakes re-drilled to 5x4.5", you'd have a little more room to the outside and less to the inside. Which honestly would put you pretty close to rubbing on the inside, especially with the extra sidewall flex those tires will have. 275/60/15's would fit easy, but, they aren't recommended for a 15x10" rim, they'd be better on a 15x8 or 15x9.
