Be carefull about the whole "home made towbar" thing. The current law, as i understand it from my sister who's in the police, is that the only legal towbars are those certified for the car. Legal means legal to have fitted, so you can't argue that you just aren't using it! Thus every vehicle has a list of towbars that can be fitted, and if you have anything other attached to the vehilce you're breaking the law.
Having said that, it is highly unlikely anyone (in the police) would ever check, or know what they were looking for (my sis had to look up the information, she didn't know it!). However, there are apparently some cars that have NO listed towbars, making any tow hitch of any kind illegal on them. She did know these off by heart, although the only one i can remeber was the Audi TT.
p.s. if you want a sports/tow car, buy a Subaru Legacy 3.0Rn Auto or a Forester 2.5 XT Auto. Both 0-60 in about 6 seconds, both legal to tow 2000kgs, but will pull much more. Both 4wd with limited slip read diff. Seen a 2.5 Legacy, (owned by above metioned traffic policewoman) pull a 7.5tonne horsebox across a field.