This is on a 99 A4 2.8 quattro.
couple questions:


1) how do I determine the hubcentric size when going to purchase a set of them? I have a set of 19's, I think 8mm spacers. I got the spacers at the local automotive shop think they are 5/16's and was told that comes out to be 8mm...but on a ruler it seemed more like 5mm. I'm using the 32mm aftermarket bolts to keep the rims on there tight.

2) I was told only the dealership can do the alignment...but while they had the car up they noticed a noice coming from the steering/rack I was told. I never noticed it before with the stock rims/tires but while driving you can hear a clicking noice as the wheels turn. Steering seems nice and tight though. Any thoughts to what that could be? Or what to check? He was certain it was from the rack he said on the passenger side. Thoughts?

 

The Centre for your Audi is 57.1mm.
So, if for example your aftermarket rims have a 66.6mm core, you will need hubcentric rings that convert 66.6mm to 57.1mm.
Hope that helps.
Cheers.