Watsonian are an old established firm and they used to be the U.K. Royal Enfield importer, so they know the bikes. I've spent a bit of time studying the Cozy and it would be my choice but that's a matter of taste. The other option you have is buying second hand. Some of Watsonians sidecars aren't bike specific so if you located a second-hand one, before you buy it contact Watsonian to see if there is a fitting kit and instructions available for your bike. I got an obsolete sidecar and they were very helpful and able to supply most of the parts. For the parts that weren't available they gave me copies of the original plans, so I was able to fabricate my own. One other thing worth mentioning is allow for a set of heavier springs for the rear shocks on the bike. It does make a big difference to the handling when laden. I don't know where about in the world you are, but in the U.K. when you fit a side car it changes the taxation class of the vehicle and the registration documents have to be changed etc, so it would be worthwhile finding what your local bureaucrats require before you decide to buy.