varaible boost controller

i was looking at a turbo kit and it said that you could get 18 psi with a variable boost controler, now i asked around and not many people know what that is, anyone has any idea what it is and were can i find one?
before any of you guys say it, i have already checked FAQ

hmm... i guess just a MBC... thats what i have, and i can go WAY past 18 psi on my controller...

A variable boost controller means you can have two settings. Why would that make a difference unless they meant something else.

:screwy:

yeah, y does it matter? meaning it can hold 18psi for short periods? i dont know...

well th kit says you can get 7-9 psi out of the box, and up to 18 with the variable boost contoller.

so in other words the wastegate is sprung to 8psi and with a boost controller you can raise it.