I have a stock suspension 06 Mini cooper s Checkmate, and am going to put some momo next anthracite rims on it which are a 17x7 and a +42 mm offset. I was looking at tires and what is the difference in performance, corner, etc of a 215 vs a 205 tire. Is it worth getting a 215 over the 205? I don't track just driving around town and on the highway. I have goodyear gt on the stock rims currently.

 

If you're not competing on the tires, the practical answer is nothing significant. The actual choice of tire model is going to make a much bigger difference hna the 10mm of extra tire. If you're looking at 215 vs 205 in the same model, you couldn't actually say without testing them.

I tend to stick to 205 for street tires just because that's stock, I might go to a 215 if there were a particular model of tire I wanted which wasn't available in 205 (and was in 215).

 

If you plan on using them in the winter....go narrow....they will "float" less on top of the slush....and they are less likely to tramline in my experience... And will do better in the rain....
Wider tires do have their place....but for a daily that you will not push...narrow might be better...Slightly better mpg too if you care...

 

For an 06 MCS on stock suspension you can choose-

215/40-17
205/45-17
215/45-17

All of these fit but 40 series sidewall is firmer riding and limited tire selection, more towards handling and performance or competition.

205/45-17 is a good place to start and ride comfort and low noise have more to do with which tire you choose rather than size alone. Anything non runflat is going to be more comfortable than any runflat. Runflats come in 205/45-17 and if you need them for safety reasons then this would be the size to use.

215/45-17 is fine with your car and allows for a much greater selection of tires whether for more performance like a Max Summer tire or for more all season use and longer treadlife like an Ultra High performance All season or Grand Touring All Season tire.

If you are doing only daily driving and commuting then you don't have to go with a Summer tire. You will get a little less crisp handling for more ride comfort, lower noise, and better treadwear using an All Season tire. If the weather gets cold where you are even if you have winter tires then an All Season allows you to drive in temps under 38 degrees.

For the best blend of good handling, three season use, reasonable treadlife with decent comfort consider UHP All season tires in 215/45-17:
http://www.tirerack.com/tires/survey...wws=N&showcm=N

 

The reason I like the wider 215/45 tire is the sidewall of the tire bulges out beyond the rim and helps to protect from curb rash to the wheel.