Personally, I don't drive like a maniac in GTA. Having realistic damage model would always be good. Think about having GTA:SA damage model in IV. It's basically the same thing. Once you have had such perfect damage system, you don't want to go back to the old one.
Don't forget that most manufactuers write 1ms just because their gray2gray response is that low. They usually are just as responsive as the bad and slow 5ms ones.
Afaik, you can't just wave a huge magnet over there. It has to be a proper one, usually a simple circle loop AND powered from wall socket. That's what I used to fix my CRT's back in the day.
Also, such fault could easily be GPU related too. Seen plenty of that stuff.
Edit: I've also fixed purple spots with that "reset" kind of thing. I can't recall the name of this process but basically it jitters the screen a bit.
Yesterday my cat was cleaning my fingers. Basically I put my fingers together so her tongue got stuck in there. She started pulling, thinking that it's a really dirty spot.