welcome and congrats on the ride
the iX's look nice as is with the iS trim, 15" wheels, fender flares, and side skirts stock. thats good enough imo, it should still stand out from other e30's. the M3 exterior conversion can be done, but it would be very costly. you would need a whole new trunk, the M3 fender flares wouldnt look good unless you got spacers for the wheels, then you would need new sideskirts, and the M3 front would not fit right unless the flares were installed. there are much better options like the M-tech2 kit for non-M e30's, i think it is even possible to get a M3 look-alike front spoiler for regular e30's. and you can always get a M3 style rear spoiler to put on your trunk, but still wouldnt look like a M3.