I don't have them, but they do look sweet. I have the considerably cheaper Pro3i arms. These are a nice product, well designed and made. And they definitely give you a significant drop. I went with poly bushings ... sphericals are brutal for a daily driver.
What kind of wheels/tires are you running? I have 18x9.5" with 275/35s in the rear and I'm a little worried about the tires rubbing if I lower it another inch.
So what is your total drop in the rear with the Pro3i's? I have 1.6" right now, and it would be 2.6" with the new arms.
I just installed these last night. Very good quality. With the seat all the way down, yes the additional lowering is about an inch. It actually may be more. I installed them w/ MRT street spings, and its way to low with the seat all the way down. I will be adjusting mine back up at least 3/4 of an inch. With the MRT's I'm lowered about an 1 1/4 in the front, and with the seat all the way down in the LCA's I dropped a tad over 2 1/4.