It sounds like ridiculously low mileage for a car of that age. You know the old adage: "If it sounds too good to be true, it probably is." I have looked at a lot of 850's to replace the one I currently have. It is important to know: 850's are notorious for the odometer breaking. The speedometer will continue working fine, but the odometer breaks. First, people driving it won't notice for a few months just because people don't bother to look. 2nd, if they do notice they won't get it fixed because of the price ($600 at stealership) then they keep driving the car for a few more years putting 30-40K more miles on it, and just before they get rid of it they pay someone cash to fix the odometer and don't report it. I'm not saying that the current owners of the car are doing this to you. The people they bought it from may have done this.

Solution? Carfax report couldn't hurt. Then take it to a Volvo specialist and retrieve the true mileage from the engine computer. It's stored there. If there are two boxes on the front of the engine computer on this car you can get it yourself, no tools required. Search this site to find out how. The engine computer on the 850 is a black box with a hose coming out the top corner to the radiator fan (cooling hose) on the front passenger side of the engine bay.

Other than that check to make sure a timing belt was done at 70K. You will have to keep the flame trap clean (simple and cheap) if it's a non-turbo, if it's turbo you will have to clean the vent box @ 100K (requires removal of intake manifold apx. $500 @ an independant shop).

I reccommend turbo's. The non-turbo's just don't have enough power for my tastes to get on a freeway.

Sorry, don't know anything about the third row seat.