I assume since you have metric tires on metric wheels, you will be buying new tires and wheels.
The 225/45-17 is too short for an E34. It will give you an effective lower gear ratio and throw your speedometer way off. BMW's are already about 5 mph optimistic. If you ran a 245/45-17, that would make the speedo almost perfect and there is clearance with most 17" wheels. If you are going to buy new wheels and tires, why not look for some E39 wheels and tires to swap onto your 5er. The size you are looking at is more of a 3er size, no?
1992 535im, 17", Euro M5 Throwing Stars 8's & 9's, FK-451 235/45s & 255/40s, M5 Sway Bars 25/20, Conforti chip, Lowes Ram Air, glass sunroof