I have the Poly installed on a 2.5in lift and with them at their shortest setting the swaybar is about 5 degrees up from horizontal, so you would not want to put them on anything lower without modification.
By modification I installed a rear set as well, but at their shortest setting were way too long. So I bought a good quality tap (1/2in 20 TPI from memory) and extended the thread down the tube another 2 inches then chopped 2 inches off the tube. Worked like a charm
I haven't seen the JKS first hand, but would still recommend it over the other. Whilst the other (and the Poly) have the stow pin, the JKS remove completely so dont need it.