They are fun with over 400 bhp thats for sure. I have never driven a standard one but I guess it would seem pretty slow compared to mine. Maybe consider getting one with a good, non rusty body but with a standard or knackered engine and rebuild the engine to how you want it?
The other thing I would advise you to do is make sure if you get one already modified that there is proof of whats been done and who did it.
I have owned mine for nearly 20 years and have all the history and paperwork of whats been done to it so anyone could see its genuine.
Keep looking , there will be one somewhere!