My brother had one of the first 240zs and like you, I have always felt I needed one. I have enjoyed this car so much, I bought 2. Performance and NIsmo. The only car I've owned that puts a smile on my face while driving.
To be more specific, I put an after market axle back on my nismo and was wondering if putting the orignal nismo exhaust on a performance would be worthwhile for a different exhaust sound. I do another axle back for the performance but had the thought of using the nismo exhaust instead.