Awesome question because I'm in the same boat. I'm about to upgrade from 17" as we'll
Here's my experience on my e46; I had 19" VMRs. I bent 3 rims on the highway in 3 months. I was DONE! I sold them immediately. Picked up 18" csl reps off eBay for 500 shipped.. More comfortable, less bumpy, more forgiving. Had them on car for 3 years including through winter and never had an issue.
I'm pretty sure ill get 18" again. Plus I'm going black wheels and I feel when it's black wheel on black tire that the size isn't noticeable as much because its just a big black circle lol.