I also bought mine from a member of the ZRX owners forum...ZRXOA. I posted a "Wanted ZRX Shocks" ad on the forum,
http://zrxoa.org/forums/forumdisplay.php?f=137 , and got several responses.
The shocks top bushing is the right size. The bottom bushing is too small, so you'll need to get a 12mm bushing/damper from Kawasaki...part # 92075-1141 (you're actually ordering the top busing and putting it in the bottom). My Triumph dealer ordered the bushings using the kawasaki part number. Cost was about $10 for the pair.Or you could use the Thruxton's bottom bushing, but then if you wanted to sell the Thruxton shocks, they wouldn't have thier bushings. I don't have a vice, so I used a threaded rod, 1" fender washers, two nuts, small socket and large socket and did something similar to Pie's method. Your mufflers may touch the shock's springs, so you might need to use spacers between the mufflers mounting tab and the frame mount...I did.