Pete, I'd stir clear of this one. There is too many Crossfire out there in fantastic shape for cheap so why go for a rescue vehicle with tons of issues. Sometimes it makes sense to pay a little more but then not having to put a bunch into repairs.
These cars don't have a lot of problems if they were well maintained. Usually if the interior and exterior looks like crap you can tell the previous owner(s) did not take pride in ownership.
The little common issues that Crossfires have can be easily rectified if you spend a little bit of time on this forum and are willing to learn how to fix these cars.
If you don't want to work on them yourself it's best to approach an independent repair shop that is used to work on German but specifically Mercedes vehicles. Given that the car is a Mercedes SLK under it's skin, shops might charge a little bit more than if it was a Nissan Altima.
All that said, these are super fun and unique card that can be had at low prices if you just search for a good one.
Makes sense to check the Marketplace section of this forum but also, join the Crossfire Facebook groups of your area so that seasoned owners can help you in your search.