it can be done but there are a few hurdles. firstly the wheelbases are very different, secondly the VW beetle is Rear engined (flat 4) whereas the viper has a front engine (V10). i think building a viper on a beetle frame is insane, you're much better off building it on a cresida or some other (cheapish) large RWD vehicle so there is less modification required.
personally i think you are better off getting a fibreglass body made here in PK, it'l be cheaper and you can have it built to your specs. also i'd suggest you dump the VW idea and build it on a larger donor car with a front engine/rear drive setup.