How about a turbo instead? I know you didnt list it as an option but it could very well be one and for less then a new supercharger. If you dont mind having a used turbo I bet you could have the kit made and put on the car for under 2k easy enough.

The reason I say turbo is that with the stock short block your better off not hitting it really hard all the time. A supercharger and juice both hit very hard and thats not good for your stock short block. Where as in a turbo comes on slower and is less violent in the hit.

Just my opinion.