18s vs 19s of the same weight and tire (and 18s are easier to get lighter), 18's ride better, handle better, accelerate better, brake better, and are cheaper. IMO, they look better as well-- purposeful instead of stylized, which is the character of the entire car. So, I can't see going 19s.
I'm running the stock style 65s for snows, and 18" BBS RG-Rs for summer (light and strong). I'm running silver, but if I had a lightly colored car I'd be running BBS's diamond black (which isn't black at all). OG could pull off either color, imo.
What I like best about them is that they don't look overly aftermarkety:
The LM's are better matched to older body style cars, IMO-- they look AWESOME on e30s/e28s, but the e39/e46 is too rounded for them. Plus, they're heavy (though they are STRONG).