Bro... if you're thinking about 19" againts 18", then I say keep the 19" on...
You see - beamers are rear wheel drive cars - therefore you don't have drive shaft problems in the front as the power is trasmitted to the rear wheels that are not required to turn... so, you won't have drive shaft problems like those on japs cars (front wheel)...
On the potholes - yes, you need to be careful, but then again even on the 18", you still need to be careful all the same....
On the cost of tyres - well, how often do you really change your tyres? once in 2-3 years maybe... the diff btw the 18" tyres and 19" tyres over that period, would be insignificant...
At least the 19" would look awesome on your ride and not many would have them.... Rims bro, are like pussies - nothing under 18! Hahaha....
HAPPY HUNTING! (for your e46 that is....)
