if i get 16x7.5 all around, i could run 215/45/16 without rubbing issues correct? (e30). also, with 16x9 with the same setup how big of spacers/fender rolling would i need to make it viable?

yes, the 16x7,5s will fit fine with the 215/45 tires. Rubbing problems don't usually depend on the size of the wheels, the offset and the lowering are that counts. I recommend 7,5 wide in front and 9 wide in back, offset will be around 15. Front wheels should be then 205/45 and back 225/45 or 215/45. BTW Brock B1's are very nice rims :thumbup: