I got them from amazon, right around 200 bucks. There is no way to adjust them vertically.
I did the install myself, took about 1.5 hours, but that was because the wind blew the instructions away a few times with me chasing them.
The instructions were not spot on, the middle two mounts on mine had existing nuts welded to the body while the instructions said to use the clip-nuts.
Just mount everything and line if all up well before tightening anything down.