well, the hope was no bodywork - that the arse end of the 981 is wider than the 986 so that the diffuser would fit inside the bumper cover with no trimming. the diffuser appears to attach at three places on the muffler so it would hang suspended from that with no body contact.
i could buy this:
Aluminum Utility Sheet 3003-H14 1/8 .125" x 24" x 36" | eBay
and these:
Dodge Viper 6 Rear Fins / Diffusers | eBay
and three exhaust hangers. i could make a template out of cardboard, cut-out the sheet alu, roll the rear lip (i have a friend with a sheet metal roller) fasten the fins and hang from the exhaust. thing is, with shipping i would be looking at $300 just in material. given that time is money, it would be nice to just buy something.