The first to do that were Porsche themselves. I seem to recall they used a MK1 Golf to test the V8 before the 928 was launched.....Must have scared a few drivers at the time.
Then a Swiss guy, Franco Sbarro did the same, had to widen the shell and get custom front and rear screens for the car.
http://www.espera-sbarro.com.fr/modeles/1983/golf300s/golf300s_en.html
He also built a mid-engined Golf Mk1 with a 930 engine instead of the rear seats. Installed a hydraulic pack to 'spilt' the car open to get to the engine.
http://www.espera-sbarro.com.fr/modeles/1983/golf_turbo/golf_turbo_en.html