I havent read through the entire thread but thought I would share some thoughts, that may or may not have already been mentioned.
The Nissan 350z for what it is, give or take 300bhp, rear wheel drive etc should in my opinion carry a much greater insurance that I have found it to.
Ive always wanted to get into the fastest car possible since passing my test, but insurance wouldnt allow it. I paid £1600 TPFT on a 75bhp 1.2L Clio in my first year of driving. I then bought a MK6 Fiesta Zetec S and then finally and currently into Fiesta ST500.
At 20, insurance on the ST was 800 fully comp, at 21 my insurance, when I finally get round to purchasing a 350z is just over 700. I was also interested in s2000s. Considerably down on power over a 350z and a much lesser engine capacity however they hold a huge insurance premium far greater than that of a 350z.
I couldnt believe that how cheap the zed was on insurance and that was a deciding factor on what would be my next car.