52mm should be the correct diameter. I'll be selling the Woodcraft clip-ons from my 06 S3 shortly. I'll post with pix in the sales forum. Let me know if you're interested.
Cheers,
Zohar
I sold them because the Woodcraft bars were a little low for me. I'm now using Tommaselli adjustable clip-ons that have a bit of rise and are adjustable in every direction (this might be a little disconcerting). http://www.motomeccaspares.com/shop/...eed=tommaselli
Zmann,
Do you have any problems with the Tommasellis clashing (physically not asthetically) with anything on your bike, also how do I find your gallery?