Hi.
Just check new rack's part number, if it begins with 1K0, it will fit. Now it depends what you have on your car, if
your rack begins the same then no problem at all, if it's 1K1 then you need new wiring loom to fit.
3gen racks (1K0) was as an upgrade to older generations, and could be fit to A3s from early 2003
So you always need to check PN and not the year of car it was from.