try checking out these sites
http://www.escortracing.com/
http://www.escortgt.com/
they have some info on parts and some modifications, but not too much on rallying. Being an owner of a 94 LX, I can't give you too much firsthand info on rallying in a GT, but it sure is fun in the LX. My car has some wicked understeer(well, that might be the driver) on tarmac, but is a tad more controllable on dirt. I've ridden in a GT once, and the handling and power seemed to be decent, but on the LX needs more horses and stiffer springs. I know that they have the same chassis, so some suspension parts may be interchangable. Since the LX seems to be much more abundant than the GT, some spare parts may be easier to come by.
I'm pretty sure that the escort is very similar to the mazda MX-3 in the same way that the probe = MX-6. I've been told that the chassis is the same as in the mx-3, but I have no idea about the engine. I think corksport (
www.corksport.com) may have some stuff for the escort. I know that weapon-R has made an intake for it, that was a few years ago, so I have no idea about the availability of it. I have run the LX in a few rally-x events; it didn't do too great, but I am also still learning how to drive.
So far my LX hasn't broken, but I don't romp on it too much. A slight wheels off the ground now and then, a couple of wheels in a ditch, but nothing too serious. It seems to not mind the cattle-guards too much either.
To the best of my knowledge, this info is accurate, but correct me if I'm wrong.
Mike