Well, I'll have to post some pics in a final update later, but the car made the whole trip (2800 miles!) without any further issues. It's really quite elastic between 80-100, although I wouldn't know since I never reached those speeds.
Seriously though, it's a pretty good long-distance freeway cruiser, and once I get rid of the exhaust vibration at 70 and the exhaust leak that required us to have full ventilation all the time, it'll be a great long-distance car. Who knew I'd be driving a car I got for $250 on craigslist this far (okay, to be fair I've put some work into it since then)...