Fitting E36 M3 front brakes to a 328i is a clean swap, because the hard part is already done: the 328i is 5-lug 5x120 like the M3, so there's no 5-lug conversion to do first (a four-cylinder 318i would need that step).
The M3 front uses larger 315mm rotors on M3 caliper carriers, so in practice you're fitting M3 rotors and M3 carriers (the caliper bolts to the carrier), and you'll need 16-inch or larger wheels to clear the bigger discs.
**W
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