If it was me I'd go for a G60 over a Rallye due to the fact that they're quicker than a Rallye and you don't have to worry about the transfer box going. On my old Rallye the transfer box cost me a lot of money and plenty of pain.
I got this advice when I was looking to buy a rallye -
if the charger hasnt been done, it WILL need doing pretty sharpish so you can argue that point to get more money knocked off it.. good rebuild with porting + pulley will sting you about 500+ notes.
the tracking on these is never set right, so look out for uneven tyre wear as usual, and low speed vibrations.
steering racks go too ! "clunking" from the rack when parking is the dead giveaway, it'll usually vibrate at a certain speed too (mine vibrates at 60mph.. just have to accelerate through it )
interior trim bits are a hard to get hold of.
if its on standard suspension, it'll feel a bit wallowy.. tbh you want coilovers on them anyway to get the most from it, any squeaks from the rear when going over bumps is usually bushes, so not the end of the world.
you really need to get the thing out on an open road and up to about 90mph to give it a proper test, hammer it too.. because lets face it thats how you drive a rallye... at those speeds you can tell if the diff bearings are sound... bad vibrations when accelerating at high speed is a sign of knackered bearings. now they're not THAT expensive to replace, .. so you can either use that as an excuse to walk away... or be a cheeky git and try to get the car even cheaper claiming it costs a £800 to fix
the biggest thing you want is loads of history for the car.. there's no excuse for not having it really unless it all went up in a house fire !
apart from all that just watch for the usual stuff when buying any car.. rust.. leaks.. bad panel/paint repairs.. cambelt .. any smoke or noises from the engine etc.
Go over to
www.dubforce.net/forums for loads of G60 info