Do i have to use the two vacumn ports of the HKs wastegate,that is the top and bottom with my Apexi boost controller or can i use the bottom vacumn port only.

 

You should use both. Manifold pressure directly to the bottom/side port, and connect the solenoid to the top port. It is probably possible to just use the bottom port and bleed air with the solenoid (this is the common approach on stock wastegates), but all the setup instructions for the various boost controllers I have seen recommend using both ports on the wastegate. Note also that you will need to use different ports on the solenoid for the single bleed versus two port setup.

-Max