Hi Johnyjn,

i can't answer all your questions for you, i'm sure someone more in the know can.
But I hve the touring car version of the getrag box fitted to my sierra.

prices are like everything nowadays, if someone wants one they will pay whatever you want, if your selling its whatever you can get. There was a time when £4,000 plus was the norm, now i've seen them on ebay for anywhere between £500 and £1,500. The fit of the box is not to disimiler to a standard box, exept in lengh. Also there is a quick release end on my box for pulling the prop out quickly, but it may just be unique to mine as it is heinz 57 of mad bits. I cant say with absolute accuracy, but I think the gearing is longer on the touring car box than the grp a rally box. I know mine is. but again it could be just mine.
If you fit one you'll never go back to a t5 lol.