I've got a '96 850GLT wagon, kissing cousin to the V70. No, it won't fit a sheet of plywood, but it's still got a ton of room inside. It took some Tetris like moves, but I was able to fit an entire twin size bedroom set (except mattress) inside the car... We're talking dresser, night stand, bed frame, headboard, footboard, flat boxspring. If the V70 uses the same a/c system, the evaporator is near the firewall, supposedly it's a b!tch to change. So if the a/c is out, either expect to just live with it, spend a ton of time trying to replace it, or a hefty bill to have someone do it. My motor is interference, I'd assume the V70 is the same, so check timing belt. I know they're very sensitive to the type of spark plug and wires used, they seem to only like certain kinds.
That said, I really like my car. Mines a non-turbo with an autotragic, so it's slow as hell. But it runs like a top, is very comfortable, has tons of room and drives real nice. They'll run forever with proper maintenance. Gas mileage is so-so. I'm averaging about 21mpg.
I've since added a set of Turbo rims, but this is mine.