The tires are part of the suspension. Some might do better with an small diameter wheel and larger sidewall and vice versa.
For me it really comes down to cost and selection. There are a LOT more choices at MUCH lower prices for 18" tires vrs 19" tires.
2015 F34 328iX GT Glacier Silver
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red