I am planning to by Porsche 911 1976 or older (this is due to
Norwegian tax system).
I recently brought a 1977 911S to Finland. I got it registered 1/2 month before Finland changed it automobile tax (no more vintage cars). As with your soon to be owned Porsche, it had to be over a certain age otherwise the taxes jump. And were not talking about 1000 euro difference, I mean really jumps.
The one thing that I had not realized is that my 1977 was build and registered in 1976. Therefore I could have brought a 1978 911SC instead. I don't know would it have been worth the price difference.
Another bit of advice. If you think you must do repairs or something so that the car passes inspection, e-mail them and ask! DON'T USE LOGIC, it just doesn't work. For instance I had to fix the windshield washer pump since it is mandatory. Latter I replace the speedometer which was in mph and had a broken sensor. A speedometer is not a mandatory requirement in Finland, if you have an RPM meter or other way of judging your speed. It is like a cup holders, it is just nice to have ;)
My 0.02 eur