I'm putting a set of Rondell R58 wheels on my car, and have a few questions:

rondell_58_17x10

1. The wheels are for a BMW and are not hub-centric. With the wheels came a set of plastic rings which fit in the rear of the center hole. Are these the "hub-centric rings" I've heard of, and do I need to use them? In an email, Andris Skulte said most of their adapters are not hubcentric, and they've never had a problem, so I'm wondering if I need to use them.

2. The center caps that came with the wheels will not work, they won't clear the grease cap on the fronts. I've thought of having the wheels machined so my stock center caps will fit, but I'm not sure I like the way it looks. I've also thought about going with a "push-through" center cap. There are literally hundreds of them listed on summitracing.com. Does anyone have any thoughts?

3. The next issue is adapters. The fronts are 17 x 8.5". I've measured the wheels myself and the actual, lip-to-lip width is 9 3/8", and the backspace is 5 1/4". The Skulte website says the maximum backspace for the front is 5". I'll be doing Ed Miller's C5 brake upgrade at the same time I install the wheels, and Ed says his upgrade makes the front track .3" wider. The Skulte website says you can run spacers no thicker than 1/4" wide, so, with the increased track width and a 1/4" spacer, will I be ok on the front? Also, how thick are the stock spacers that come on many 3rd gen wheels?

The rears are 17 x 10. The actual lip-to-lip width is 10 7/8" and the backspace is 6 1/16". The Skulte website says the maximum backspace you can run is 5.85", and Andris says the thinnest adapter they make is 3/4". Will that work? Will I need to roll the fender lips with that combination?

4. And finally, the tires. What would be the biggest tire I could run on the front and rear with this setup?