Common problems include seals and gaskets, rad, window regulators. The 540 isn't as reliable as the 528. Your cats might go. Forget about buying OEM replacements. Buy aftermarket for a hell of a lot less. Ball joints and wheel bearings may go at some point in your ownership. O2 sensors (it has four of them). Your headlight lenses will pit and dull after a lot of highway use. I went through a bunch of cracked fog lights. If you have the style 5 rims, the clearcoat may pit and peel. That's a lot of torque for that tranny. My auto tranny went through a rebuild.
If you get it properly checked out and it's good, pick it up. Expect to spend a little money keeping it in good shape though.
Last edited by Euro; 11-13-2009 at 04:26 PM.