Watts, it's a shame you didn't test drive the GR86, it is is really quite special, you do need some Rwd experience to explot it, which is not instinctive if you have stepped out of a Fwd GTi.
A friend wanted my CS and offered very favourable terms against his new GR86, it was tempting, but the lack of hatch stopped the deal. with 3 x 2 seaters, i need at least one practical car.
I know 2 people who have gone from Gti CS & R to M2 comp,,,,,both moved on within the year. I can't really see the point of a 230i, you will always lust after a car further up the range?
Both moved on to Gr Yaris and love them, they are not as small as you might think, it's surprising, particularly when parked next to a mk7 Golf.
The BMW, 86 & Vantage you mentioned are all Rwd, do you want to go in that direction?
No bias, the Golf is my only Fwd and I like the way it drives.
As for the elderly, how often do you drive them about? I often take my Mum out in a bespoilered Lhd 911, being Lhd she is sitting on the offside giving the impression she is driving? The only real issue was with my dad iin my Elise S1, he could get in, but it took some time to lift him out.... If you avoid Elise, Caterham & Morgan, you will probably be fine?
