Would this be feasible to do on my E36? I know with a stretched tire it would be fairly simple, but I would like to run a 245 or 255 all around. could it be done with enough fender rolling and maybe slight flaring?

Yes, definitely feasible.

Front might need 5 - 10mm spacers depending on your suspension setup. Fenders should be rolled at least.

Rear will need fenders rolled. A bit of flaring might be needed depending on your alignment. I think anything less than -2.5* camber and anything more than 3/16" toe IN will give you rubbing problems (although that depends on your suspension setup as well).

im on stock suspension. im gonna go straight to coilovers soon, hopefully along with UUC adjustable LCAs out back.