I did a ton of work on my 240, including conversion from an auto to manual transmission, head gasket, and timing belt. After looking at the 850 engine layout, I wasn't overwhelmed. I think for the most part, work on this car will be largely the same, but some differences. First off, those jobs requiring things like engine mounts and rear main seals will be worse because of the transverse engine. Additionally, the car as a good deal more sensors with the ability to fail. However, it appears that the majority of those sensors are for emissions purposes, and wouldn't leave you stranded on the side of the road if they failed. You'd just have the pesky check engine light and a bit of work tracing the problem. I'm willing to deal with that increased complexity if it means driving a car with an engine that can go 300K miles and with a great deal more ride refinement. That's the give and take I see between the 240 and 850.