I like that your standing up for your look. Here we have you take of look and driving on smooth roads from place to place and doing shows. Then Dave's perspective driving hard on back roads and crap roads around town. (I have the crap roads too). Do what makes you happy. That's what having a MINI is about. Get some pics when you have them on.
The 19" will have a rougher ride than 17" based on the simple fact of less side wall. Comparing against run flats doesn't count because they're crap. A strut suspension design changes camber as it moves up and down. A larger side wall allows the tire to keep the contact patch on the ground through the travel. It's why a lot of the guys that autocross MINIs go to 16" some even 15". Then you have the weight difference. Larger wheels weight more. On the track or hard driving you can tell the difference. My winter set up is almost 10lbs / wheel more than my summer set and I can tell the difference.
Again go with what makes you happy. If you don't like it later change it again. There are a lot of guys on here that have gone through different wheels for a number of different reasons.
