TV cars..... I have first hand experience, as I was the (very, very) lucky winner of the car on Channel 5's Classic Car Rescue. I've done a lot to it (and had a lot done to it) in the three years or so since I've had it. The engine and suspension have undergone full 595ss Abarth spec upgrades for starters.
When I got it the body work was fundamentally excellent. There was quite a lot of trim..... missing..... shall we say, and a very helpful owners club member helped me with quite an extensive missing parts list.
The mods that they did to the top of the engine (head, the high lift cam etc) were also excellently done, but they didn't touch the bottom of the engine at all (the centrifugal oil filter still had 40+ years of crud in it!!!). It also hadn't been tuned, basically it seemed like they'd just put back together and started it.
It was no doubt restored in haste for the TV cameras, but hey, I'll certainly never complain. The raw materials of a magnificent, well restored car were there, it just needed a bit of a push along with some "ownership" TLC.
It was (and is) a great car. It's a very different one today versus the one they delivered, but I always tip my cap the Channel 5 just before I climb in to it. The cost of the text message to enter the competition was the best £2.50 I'll ever spend!