The best place on the internet for FAQ, model information and stuff like that is the Volkswagen Cabriolet & Rabbit Convertable FAQs site. Also, the VWvortex Forum: Cabriolet is a good place for info. Listed below is some information and modifications I wrote down; mostly when I had my '84 back around 2000.
Replace your top
Conv. blue-prints
The Conv. Boot
Dechromed Grill
Volvo 240 spoiler
How to remove your plastic trunk lid cover
An add for the 1984 Rabbit Convertible Wolfsburg eddition
Click here to see where the rabbit gets reinforcing for cabriolets
