Hesitation under load
 

Hi, my Bugeye WRX seems to have a slight hesitation when under load, but only when at full boost. I recently discovered a boost controller had been fitted to the car by the previous owner as well as a boost gauge in the drivers pillar! I have played around with this andset it to 0.9 bar on full chat. I can only describe it as pulsing off and on boost. Could this be down to the boost controller or am i looking in the wrong place ie plugs, coilpacks or early signs of MAF failure. In past experience plugs or coils would show signs of breaking down under load but whilst accelerating from slower speeds and i thought the MAF heated up every time the engine fires to self-clean? Lots of questions i know but i would like to try and sort this out. Help appreciated Mark. Also, does a 52 bugeye have a 2 or 3port controller as standard as my aftermarket has 3 pipes attached to it!