Thanks for all the feedback. It is all in my notes!!
I pulled the trigger. I found a $50 off code on Retailmenot for orders over $250.
The retail on this was $729, with $100 off and free shipping, and then with the additional $50 off, it came to $579. I had to pay sales tax, but that was only about $36, so I'm still ahead of the game with the $50 off.
Oddly enough, it kept kicking out the $50 when I tried to pay through PayPal

, but when I did normal checkout it stuck...
Now to decide on the axle... I really want brakes.
I may sell the axle without even installing it and order a torsion axle with brake flanges. I think this would make the axle more marketable, as I could sell axle, springs and mounts, and even the wheels as a package. Or I could just get a regular axle with the brake flanges and mount it with the supplied springs.
Any suggestions?