I know the PRV +T would be expensive, but man, they sound beautiful, and other than John Lane, I can't think of many who actually play with PRVs.
So, for the swap, I'd be looking at rear diff mounting as the biggest pain... Not too terribly bad, considering the uniqueness of the build. Of course, I may get my hands on a Pug and decide to leave her alone and drop a PRV into my 740 wagon, instead. Either way, I'll have something fast and wagon-shaped, and something unusual and French.
I do agree that the Peugeots are better looking cars, though it's not terribly hard to get better looking than a 240 or a 740. The only reason I'm not daily-driving a Peugeot wagon instead of my 240 is that it is unusually difficult to find one in northern Alabama, while Volvos are a little bit easier to find. Not much easier, but enough easier that they exist.