I'm not familiar with the product itself, but do have friends that have added air lifts to their TV's and for the most part felt that it was worth the investment. It will firm up the TV's rear sag a little when towing, but doesn't increase a TV's weight limits.
Also, check with the manufacture of the air lift product you purchase and confirm if the system should be de-activated (or minimum air pressure) when initially installing/adjusting your WDH under loaded TV/TT conditions.
The X23J has an impressive CCC of 2,310lbs, be careful of your loaded TV/TT weights. http://www.jaycoowners.com/showthread.php?t=3866