I assume you are on a stock turbo/wastegate? No matter what spring is in the Hallman, it will be able to max out the turbo if cranked all the way down. If cleaning out the boost controller doesn't fix the problem, you could also check to make sure the wastegate arm didn't somehow come off of the flapper arm and I would also check the turbo for shaft play.

If your unable to come up with a solution, you are more then welcome to bring it by Judge Racing and we can get your car sorted out for you.