A friend of mine used to tow that way in his Boxster before he moved to towing the whole car on the trailer. Had a plate welded on to an oem towhook and mounted a ball to that. My trailer hitch mounts to the bumperette points, i don't know if i would do the tow hole method or not, bit he did it. The logic is, if it is strong enough to winch the car up a trailer...
His rig is for sale for $650 in Sarasota fl, Southport trailer and hitch, it is a newer version and nicer than mine