How about 965 3.3 s2, value wise?
compare to turbo 3.6. let's say equal condition.

That is a huge enigma. So few of these have surfaced in recent years and those that did previously were always suspect. There was one that I knew of that was still in original delivered condition. Red owned by the late "1 of 20" on rennlist possible here. It still had the Andial built engine and was in very nice condition. I know of several in black and white that at one time were local to me and they all had the engines rebuilt swapping out cams and other goodies that Andial swapped initially. Most did not retain the original parts which IMO was a huge mistake.

It is not easy to prove that the cars are one of the 20. Half retained the turbo badge the others had S2 on the lid but most important were the individual stickers on certain body panels that stated there serial number and had an ANDIAL lettering in the paper IIRC.

Now it was never clear if these cars would fetch more or were considered part of the 309 (including the 20 S2's) 964 turbo 3.3's built for the US market in 1992.

I would suspect a car like the red one should command a serious premium since it had the history of being part of the homologation process to run these cars in the IMSA race series. I am assuming the Andial Cof A retained with the car but Andial no longer exists. The others might command a premium over the 3.3's (all depends on what someone is willing to spend on a chance) but without the original engine upgrade from Andial I would say it drops it closer to the 3.3's than the 3.6's.

The biggest problem and I see this a lot with cars like the speedsters and 94 C4 wide body cars is that many had been badly treated and now they are being restored to a high level without the owners informing the prospective buyers. There are people out there replicating Vin Tags and many other parts and using pictures posted on these forums to make sure placement is accurate after panels have been replaced and the car repainted. It is very hard for the trained eye to know what is original and what is re-manufactured.

If you have an opportunity to purchase an S2 I recommend doing your research and be ready to pounce. They will not show up so readily if any trade publicly at all. Another issue is similar to the 3.6T's. So few are trading publicly the insurance companies like Hagerty still put a value of $38k on them when we all know that would just be the deposit.

thanks for your advice...Cobalt.