RE: flexing, it's possible that the mounts themselves move, not a big issue when new (we had one), but might be an issue if some of the bulkhead has rusted away na (for cars this old, you may need to reinforce the welds around the rear shock moounts).
The big issue with this series was the weak stock shock absorbers, but we never had problems, so that might be on the sedans only... and they'll all be replacement parts by now.
The engine itself is very old, and not the same as in the B13-B14 sentras that were around from 92-02, so parts won't be as easy, but there are lots of shops that still carry parts for this car.
Nice car. Very spacious for its time, decent aircon, etcetera. But at the age, you're looking at a lot of things to fix. Good for a project car, but as a daily driver... pass.
