^5 to that!
I know most mechanics shops scare the living hell out of people with what's actually wrong. Doing a cylinder head on these things is cake, some cars I know are bad, where replacing an engine is cheaper and less labor (for some reason a lot of Fords come to minds...Don't know why...
You're the perfect example of when we tell people that you CAN work on your XJ yourself, and we're here if you run into problems. Now go and spread the word about how cool the XJ's are!!!