The car I regret selling was SLR5000 .... it had buggered diff and at the time I got 8K and thought I had made out like a bandit. This was long ago when mint Charger was 5 grand.
The one I regret selling was a CK Chrysler by Chrysler (the Statesman equivalent).
My Great Uncle had bought it from Chrysler Australia as an ex-company car (it was the Chrysler Australia General Managers car). When my Great Uncle died, my Grandfather got it to tow his caravan.
Eventually he sold the caravan so I bought it off him..
Baby poo brown, with a beige vinyl roof and fully optioned - literally every option available, it had, including a set of 5 Charger R/T mags...
the 360 V8 got 12mpg no matter what you did with it - around town, open road, towing a fully loaded car trailer - all 12mpg..
I eventually sold it in Canberra to fund my move to Melbourne. ('89?)
The guy that bought it turned up to look at it in a GTHO Falcon.
It was only years later that I discovered how rare it was. I was talking to a Chrysler fanatic and told him about it. He then informed me that the CK's only came with a 318. Mine had the 360 option on the compliance plate (I had a rubbing of it to show him back then).
Turns out that because it was the GM's company car, and he wanted a 360, it was the only factory fitted 360 CK to come off the production line...