The only car I really regret not buying was an original Quattro. Wouldn't have been able to afford petrol for it but...
Always remember being in Wales and being followed down a single track lane by Michelle Mouton in her works Quattro between stages of the RAC rally in (I think) 1981. We couldn't move out of the way for quite a way as there was a drop on one side and a bank on the other. Eventually was able to move over and let her pass. Got a wave and then just saw dust she blasted it away. We had been following the rally for about four days with little sleep.
Also remember being in Bath (1980) for an RAC rally and after watching scrutinering going to the pub. Stig Blomqvist was also in there having more than a few. Found a nice corner in a forrest to watch the cars and I fell asleep standing up I was so knackered.