I'm on the fence with the dern thing right now. I was using springs and it seemed to work well. Right now, I have it held in one place...roughly feels like an hx35/14 as far as spoolup. Cooling as it sets now is not what I had expected. It's hard to beat the hx for towing with a 12v. Seems like even the slightest bit bigger compressor and I'm chasing the pyro with any kind of load. Empty with my present timing (19.5) the rear end gets squirrly at 2500 in 4th---definitely moving more air than the hx! I think with a controler like Fleece is coming out with, it would be far superior to the hx in every way. I'm gonna try a drive pressure controler before I dump it, then I'm going hx/ht3b.