Hi Mark.
Last I heard, Volvo's are one of the safest cars around in a crash. I drive a 740 Turbo wagon, have done these past 6 years or so. My car is like driving a tank with performance amongst all of these newer plastic cars.
The best way to get feedback on the Volvo you are thinking of buying is to Google it = Volvo s40 feedback or feedback Volvo s40 and go from there. It is what I did with the list of cars I thought I wanted to own, until I came down to my Volvo and the rest was history, as the old saying goes.
Whatever you decide, it is a good idea to check your local wreckers for wrecked similar Volvo's for second hand spares (about 1/3 Retail cost or less) and Volvo parts suppliers, so you don't get caught short, anytime soon.
Also find a local mechanic with a good Volvo repairs history, in case you won't be doing repairs yourself. I lift the lid of my Volvo and look at what's under the hood and close it again, pretty quickly. I have an excellent mechanic to do repairs and to keep my hands clean.
Another thought bounced by, but I've forgotten it again.
In Aussie, where I am, we have a Government Agency called REVS which provides an instant feedback of if the second hand vehicle we are about to buy has Hire Purchase outstanding on it. If It does, I wouldn't touch the purchase with a barge pole, because I could end up with paying the purchase price in full and ending up with the full HP on top of that, if the seller does not pay off the HP from my purchase price, before I collect the car, but things are probably different in the USA where I'm guessing you are.
Whatever you decide - Good Luck
BigBenn