One way of testing the VCU, I'm told, is to get it on wet grass and floor it! If the front wheels spin like crazy, it ain't working. However, whether the owner would be happy with you doing that is another question :lol: The other, less aggressive way IIRC is to jack up one rear wheel and try to turn it. It should turn, but with quite a bit of resisitance. If you can't turn it, the VCU is seized. Am I right someone???
I'd prefer someone else with more knowledge to confirm what I've said though!
The head gasket had a habit of failing. I believe the LR kit replaced some plastic dowels with steel ones and included a modified head gasket. I seem to remember something about a thermostat relocation, but this might have been with other cars using this engine. The K series engine has a very small coolant capacity and any slight loss of coolant can create a failure. We never had any trouble with ours in the couple of years we owned it, but I often found myself watching the temperature gauge.... not great for road safety!
Most people, me included, would recommend trying to find a diesel. They tend to hold their value better than the 1.8's though.