You will have to provide the size of the turbo's to give an idea of what they are capable of. that info you can find stamped on the housing or on a plate

You will need a fabricator to weld a DP for you. I am not aware of any vendors selling one premade for the HF mani. You can try to find a used one if somone is selling their homemadeturbo setup.

With the age of the motor, i wouldn't push more than 7psi on stock internals. I am selling Eagle Rods and Vitara pistons.