I had one for a few months. Not that good off road, but good on it. Well ok. Off road theres no engine breaking to speak of and you have to rev it a lot. On road it went better than a TDI, but you do not want to try towing with it. Also remember its not a standard LT77 box and the clutch is not the same either. As for adding a bigger engine it has a full with rad with electric fans, but you will need to change the box as well.
I give £800 for mine and it was almoust mint on a K reg with 77k miles on it with the clutch gone, sold it a few months later for £1700.
Paul