I have a hybrid EBC, the solenoid thats used is a MAC solenoid that holds boot and wont fluctuate AT ALL..
i've noticed that Apexi avcr, the e-boost and some other ebc (that i cant think of the name at the moment) use the same solenoids... just different stickers/colours but all the same..
for $250 it was the best bang for your buck i baught on my car.. also i think it comes on boost harder and faster...
my 2c