some reading for an answer to the above question
http://www.clubsub.org.nz/forum/index.php/topic,35842.msg504156.html#new
AnwY they work fine if u set them up correctly
Prone to some slight overboost in cold temp
I had thT issue so simply set it up on a cold night and that way that was the maximum
It made less boost in the summer
if u Wana get something like that just get a hallman pro as it controlls better than that one and is more consistant and costs less
Win all around mate