So, about a month ago, I had my A4 lowered with some H&R sport springs. It looked better, but it really made the wheels look sunk far into the fender.
I've never been one for spacers, simply for all the inherent issues that go with them... but the 'sunken wheels' were annoying me, so I decided to try a set of 8mm spacers, just to bring the edge of the wheel almost flush with the fender.
From a visual standpoint, they looked great. But as soon as I drove the car, I got a noticeable vibration at around 80km/h. This wasn't going to work...
I called ECS Tuning, and they recommended that I try their own 'brand name' spacers, and guaranteed that they wouldn't vibrate. Well, they were wrong. Another waste of $200.00 They were worse than the H&R spacers.
Then I stumbled across a company called: 42 Draft Designs. They make spacers for German cars, and they are absolutely car specific. You can order off their website, but if you are unsure, or have questions (like I did), then I'd recommend contacting John Pelton there. He is an absolute superstar, and very helpful.
He fabricated a set of spacers for my car / wheel specific, and shipped it out the next day. I just installed them, and... NO VIBRATION WHATSOEVER!
Their spacers are hub-centric, as well as wheel-centric, so they fit center on both the hub and wheel. No chance of being off-center.
Two thumbs up for this company, and a shameless plug from me...
If you're considering spacers, don't waste your time (or money) with anyone else. Go straight to 42 Draft Designs.