I would stick with 19's. Since that is the case.... LM's are your best option. LMR's are not available in anything wider than 10" in 19's. That's too narrow. I would get LM's in 19x9.5 front, 19x11 rear.
'13 M3 - Silverstone II - Sold
'04 M3 - Jet Black - BBS E88, KW Clubsports