Boost control for a 1986 Grand National

I currently have the BstC Boost Controller from Ramchargers Performance Connection.  When I first bought it, it was absolutely the best boost controller I ever had.  That only lasted until I changed turbos about a year and a half later. Then it didn't control the boost any longer.  I got no satisfaction from the company as far as problem solving or possible solutions as to why it no longer works.  Nothing.  I did learn that I was not the only one with problems with it though.  So, I guess my question is, has anyone who's had problems with this controller have a solution?  If not does anyone know of a good boost controller?  Preferrabley one that's mounted in the interior that's accurate and reliable. Thanks for any help.