you will need a wastegate actuator, universal, that is adjustable(try to find one that has a low initial boost opening) and a boost controller-there are several designs, but the simplest is simply a valve that bleeds of boost to create a boost signal for the actuator.
I like turbosmart products, quite expnsive, but the quality is there and they are easier to work with, typically you can get the actuator with a couple different springs to initially set boost(this costs round $130US) and the controller, which typically costs around $70. to fine tune the boost,
if you don't trust your boost gauge-getting a second gauge from a seperate manufacture(even another cheapo gauge works. and run a tee-so the signal goes to both gauges-if they read the same-or within a psi of each other, the gauge should be fine-very very rare for two gauges to be faulty; Don't forget, you'll really only see boost when driving, as you need the load to create boost.
