There are a couple major disadvantages to having a larger wheel. First off, you'll have a lower profile tire so your ride will be a bit bumpier and stiffer. Also, you'll have to watch for potholes, since there isn't much tire there to protect the wheel from getting bent. Also, you'll notice your car might feel a bit more sluggish, since the wheels are heavier. This can be pretty significant. Road noise will go up too by a bit. Your speedometer might be a bit off due to the larger wheel, but this is most worse with 19's. Replacing tires is a bit more expensive.
another thing to remember....if you go with a wider tire setup, expect some tramlining. this is when the steering wheel seems like it has a mind of its own on crappy roads. not a big deal, but sometimes and annoyance.
A forum community dedicated to BMW E46, E90, and F30 owners and enthusiasts. Come join the discussion about M performance, turbo kits, engine swaps, builds, modifications, classifieds, troubleshooting, maintenance, and more!