I don't know what the deal is with ford but I had an '88 t-bird turbocoupe (2.3 i4 turbo) and it was a 5-speed with short gearing and crap loads of low end torque and it STILL said not to tow anything with it. The transmission was a Borg-Warner World class (one strong F'ing tranny). I think it is actually the stress on the diff. and the axels. That's all that I can figure but my turbocoupe is dead now thanks too freezing rain and a concrete wall on I-71 so it don't really matter to me anymore if I can tow anything. I never towed anything anyway.

My advice would also be, depending on how much weight you put in there, maybe get the Limited Slip Diff from K-spec and possibly even a bigger final gear. (I'm talkin' like over 1000lbs. but I hope that those subs and crap don't weigh that much especially taking out your back seat).