I have been doing open racks for 10 years on my little Volvo v40 (abt the same size as A4)...the old bigger ones (free) will fit 4 boards and 2 sets of skies...bring the quiver..absolutely no problems.I bought the rack but would honestly fold seats down if I could. My 2001 subaru impreza doesn't have folding rear seats. The roof rack exposes the boards to the elements and makes a significant amount of wind noise. Of course you can get the carrier but that is mucho mula. I'm paranoid a rock will take a chunk out of my board out on my exposed roof rack though.
In the VW terms, A4 = MK4 chassis, which is a PQ34 chassis.GTI is on same chassis and motor
Wasnt Jetta off the A4 not the Passat