I've been waiting for this subject to come up again, because we found a way that worked well. I towed a car from the Bay Area back to Houston behind an Acura RL, through rain and snow, and it was an absolute joy. The teener tucked in behind the car, and it wasn't just stable, I think the car handled better with the 914 back there. I didn't want to weld or drill any new holes in the 914, so we took off the bumper, got two pieces of flat stock from Orchard Supply Hardware (or Home Depot), bent them in the middle so they followed the countour of the car (nothing fancy, we put them halfway onto the curb and stepped on the unsupported half) drilled them so the bolts went through the vent holes are in the front trunk, and sandwiched the car between the plates, one plate inside the trunk, one outside. The thinking was that we'd get more square inches for support, to be safer and minimize any damage that could be done in panic braking or whatever. We bolted on a cheap ($35 on e-bay plus $15 shipping) universal tow bar and it worked great. It was MUCH better than a tow dolly, far more stable, I towed it easily behind a medium sized car, and the pieces, once taken apart, fit easily even into a small car's trunk. And when you take it off there's no trace that it's ever been there.
From the front.From Inside the TrunkThe lights were just a cheap Harbor Freight towing kit, with the wires run inside the front trunk, out just below the windshield and into the closed driver's side door, out the back of the door and under the engine grill into the rear trunk, where the lights were held in place by the closed trunk lid.
Hardest part is removing the front bumper, everything else can be done in less than ten minutes. It's easy, cheap, and works great. It works so well, in fact, that I wouldn't tow a car any other way, unless it didn't roll or I had at least a large pickup and a full trailer.