My 96SE Duratec MTX has hit 34MPG several times. When it did, I was doing 100% highway driving, averaging probably 70MPH and the weather was hot (i.e. the air was less dense so not as much fuel was being dumped in).
Before I installed my MSDS headers, the car would only get 32MPG on the highway, so the headers have helped a bit too.
Given the right terrain and weather conditions (i.e. tail-wind), I think 35.9MPG might be possible.
