turbo psi?

That is a little low, at road speed it should hit 40. Have you checked the air to air?

 

You don't get full rack travel until 38-40 lbs.(I think, someone correct me if I'm way off), another popular place to leak is the gasket/studs where the turbo's mount to the manifold, if that is the problem make sure you use the updated studs. if the air to air and gaskets/studs check out, its probably the top turbo(it was on mine). I replaced BOTH last July and cant keep them from leaking (the V clamp holding the exhaust housing to the bearing housing).I think it is a bad casting, surly I have not gotten 4 bad clamps from 3 different parts stores.

 

You also can take the fitting out of the intake where your boost gauge line hooks up. Cleaned mine over the wknd and my fitting was nearly 100% clogged with soot.

 

A 475 Acert twin turbo engine should be hitting close to 45 psi of boost. With your boost level at 32 psi, you are not getting full fuel position(rack travel) in the ECM. This is limiting the engine Hp capabilities greatly.

As others have said you need to inspect the aftercooler for leaks. You need to inspect each hump hose and the hump hose clamps for leaks on the air to air piping. You need to inspect all of the piping between the turbos, both on the intake and exhaust side. You need to inspect the exhaust manifold for leaks at the studs holding the manifold to the head, the slip joints and the turbo mounting flange. You need to inspect the water to air pre-cooler for both air and water leaks internally. This should show up with a slight loss of coolant that can't be explained or found. The coolant will go into the air side of the cooler and be crystallized blocking the airflow through the cooler. This restricts airflow to the engine and shows up with low boost and power complaints, along with the fact you're constantly adding small amounts of coolant, but can't find where it is going.

The fitting to the boost sensor have been known to clog up over time. This restrict the boost sensor from reading manifold pressure quickly and properly. The poor responding boost sensor signal then keeps the ECM from going to full rack position resulting in low power and boost.