I had a Focus ZX3 5sp. for a number of years. I loved that car; put 110,000+ on it and sold it with 199,xxxmi showing (should have held on to it long enough to roll over 200k!
). The guy I sold it to still has it and drives it daily. It was rock solid and drove like new.
Some things I noticed with it: winter KILLED mpg's. For some reason all my Ford's have suffered with unusually severity at temps below about 35deg.
It was a battle all the way up until I sold it to minimize that loss but nothing seemed to help very much. A WAI was worth .5-1mpg in the cold, at best.
My biggest mpg gain came from dumping the factory exhaust manifold/cat combo and running an SVT full length header. That swap was worth a solid 1-1.5mpg (though obviously had legal issues). This was on a 'Zetec' engine though.
The lack of gearing options was infuriating. The car desperately needed a taller final drive but LOT'S of searching came up with nothing but SHORTER ratios.
Despite my best efforts 36-37mpg was the best I could consistently average during my commute. My Saturn bested that without even trying.
I still miss my ZX though. It was a fun car with a phenomenal chassis. Some basic suspension upgrades made that car SHINE on a twisty road.