Lots of RV people do it, most of the kits are universal. I was thinking about doing this and I still might if I need at some point, I would just use a used kit from craigslist or get the $70 walmart one. People say disconnect the drivetrain, I've heard undoing the driveshaft from the diff and just ziptie that to the ppf is the best way, but at the same time there are people who have driven cross country for years towing behind their RV and don't do a thing to the car. Some claim the trans will not be lubed properly, but those who have done it claim they have never had a problem.
Some things to think about, in some states the car is required to be registered and insured, in others it is just a trailer and needs no registration or insurance. In California the vehicle is required to be registered and insured but talking with one of the guys from XDC he has been flat towing for years and the car is a crazy aggressive drift car, he has never been stopped and never had a problem, claims cops just don't know the law so he never has issues.