As the instigator of this thread I will add the following comments:
I had Porsches for 18 years, with the majority being pre-'73. The last one was an RS Carrera replica which was correct in every detail bar the chassis number(!) which I ran for 10 years. It was fun, it was quick, it was probably lethal in the wrong hands. Contrary to most opinions, it was eminently fixable on a DIY basis, helped by the plethora of spares availability and the knowledge and helpfulness of, in particular, DDK.
I had always 'promised' myself that I'd sell it when I reached the grand old age of 70, which I did. And yes, I 'made' money over the 18 years of Porsche ownership due to their astronomical increases in values. However, over those 18 years I spent a LOT on maintenance and 'improvements' so probably broke even overall, which means that Porsche ownership probably cost me nothing....
With the Porsche itch comprehensively scratched I spent a couple of years entertaining Mercedes' with a 1991 500SL. Wafting along in the open air was quite delightful but eventually I realised that I was scared of something going wrong with the electronics which would probably not be fixable without specialist help and a bucket full of money! I was also missing the rawness of an 'early' car and their analogue approach compared to a more modern digital approach.
So the hunt was on and fortuitously MikeB had advertised his car on DDK at the time, and OKJ was bought....
I have not had much use out of the car for the past 12 months due to a house move, but this year should change that!
Impressions? Well the Z is beautifully balanced and reasonably quick for a 72 year old (me, not the car!). Compared to the RS it's plush (the RS was a Lightweight so trim was sparse), quiet, economical, fairly relaxing to drive.
A few big drawbacks though - spares availability; specialists in my area of Yorkshire; the constant questions from Joe Public (what is it?!), but most like it.
A 911S is not comparable to a 240Z - the age-old saying about early 911's is 'It's not acceleration, it's violence' stands true in my opinion. I can compare one of my Porsches (a 912 rally prepared car) to the Z - very quick from A to B without endangering one's life. A pre-'73 911 is quite capable of 'biting' you, if your own skill does not equate to the car's capability!
The choice is all down to your own personal parameters at the time of buying.... and I'm glad I made the choice.