I just picked up my new A4 - 2006 Avant Special Edition in Misano red. The dealer had done a lovely job prepping it inside and out. It shone like a new pin. After a weeks use it needs a clean. What the heck to use...? Reading posts on this forum it seems like there are a lot of high tech options out there. Previously I've only ever had Autoglym products. Are these OK or should I avoid? What about the cabin? How do they get that wonderful showroom look to all the plastics?