I have an August 1970 240Z that I've been enjoying for the last couple of years. My intention is to restore it some time soon so I've been busy buying up NOS original Datsun/Nissan parts for it.
The question for the experts out there, should I return mine to original or keep all the BRE/Interpart/Mulholland upgrades fitted by the first owner, including original American Racing 14" Libre wheels. It came with BRE front and rear spoilers, Interpart/Mulholland suspension upgrade including sway bars, adjustable camber bushings, compression rod bearing, steering coupler, BRE exhaust header. All the bits were on the car when I got it, it had been sitting in storage since the early 1980s but I have it up and running/driving now. I have a complete original suspension setup as well as what is on the car, so I've restored that with all original bushes/bearings etc. It's powder coated and all bolts/brackets gold zinced in the appropriate places.
With the way the market seems to be going, my hunch is that all original is more valuable than a period upgraded 240Z. I'll probably sell it once finished but have another 240Z that's a keeper!