Before possible wasting your time and money on uneccessary solutions.
Firstly, inspect the hose connecting your wastegate actuator
to your intercooler return pipe. It may have a split or hair-line crack,
which are hard to spot. At the cost of $5 I would replace it.
A leak in this hose will bleed off air and cause
your turbo to reach high boost levels, causing its destruction.
Secondly, before removing your dump to inspect the wastegate
valve supposedly hitting your dump-pipe.
Use a needle-nose air squirter hooked up to an air compressor,
remove the hose off the actuator and stick the needle into the
actuator's nipple and squirt some air into it.
Your actuator should open-up quite freely, it can easily be heard.
You should be able to hear wether or not its hitting the dump-pipe.
If it does not hit the dump, but opens up slowly with lots of air
pressure, you might have a sticky actuator.
In this case, your better off purchasing a 12psi adjustable actuator.
From recent experiences, it would be wise not to get a universal
actuator and bend and heat the rod to suit your application.
Purchase a U-shaped rod, if required from the turbo place.
Hope this solves your problems.
Cheers,
Bill