This spring my fiance and I had picked up our X23J from a local dealer. Got an awesome deal on it at the RV and Camping show in Green Bay, WI. Anyway, the only things that we noticed so far, is to double check all your connectors and screws for everything (something that the dealer should do), but double check it.
The first time we hooked up the to higher pressure of "city water", we had a pool of water form under the sink and on the floor. Hand tightened the connector for the faucet and all was great (after cleanup!!!! LOL). Same with using the toilet (it is the clean water fill that was loose, not the "bad water")....
Also, plumbers caulk around sink was starting to pull out....that was a warranty fix.... nothing major....
As far as towing, I have a 2003 Dodge Ram 1500 HEMI 4x4 without the towing package. I have to tow with the overdrive off and on the interstate average 8-9mpg with the A/C on..... (took a 560 mile trip across WI this summer).... I have a soft tonneau cover on the truck, so the front face of the camper is a huge wall on the highway...LOL
Good luck and have fun with the camper....we absolutely LOVE IT!!!!
Chris and Sheri