We went tow dolly instead of towbar for a couple reasons, 1 no one made plate for our 199 BMW 323i and a custom plate was $750-850 we paid $650 used for the dolly complete with surge brakes and lights.
Now we traded in the BMW for a Kia Sorento, not 4 down towable, and can still tow. If we spent the money on the BMW it would have been gone with the car. Dolly gives more options, like buy what you like vs. what can be towed 4 down.
We have towed cross country and through the mountains with none of the tracking issues or parking problems beyond 1 more thing to fit into our spot. Some places even have a place to park your dolly or trailer so you don't deal with in the spot.
Ray, Cheryl & of course Miss Molly the four-legged child
2006 Dolphin 36' F53 V10 5 speed auto 2 slides 7.5 KW genset