That is the question! I was thinking of getting the Greddy turbo timer for my car.
But I was reading the previous turbo timer posts on this forum and now I am not
sure that its worth it.

1st Is it a sound investment?

2nd how long should I let my car idle b4 i cut the engine off? For proper cooling.

3rd What kind of harness would I need to fit that TT?

Thanks for all of your help guys, I know i've asked a lot of questions...

A turbo timer is a good investment if you don't have the patience to sit and let the car idle for a couple minutes after a hard run, but a waste if you do.

You should definitely let the car idle for a few minutes after a spirited run, your turbo will be that way. If you can drive gently for a while afterwards or haven't run it hard, 30 seconds or so should suffice.

Not sure on the harness, but I hope I helped with the first two ?'s.