NOTE: If you are tuning with an external wastegate, we have found that the Prodrive electronic boost control solenoid (EBCS) works perfectly with the stock compensatory wastegate calibrations (coolant, intake air temperature, etc.). This solenoid is a replacement for the stock EBCS and plugs in to the factory wiring harness. Tuning external wastegates with the factory boost control system (ECU) has worked very well as long as you use the Prodrive EBCS. Please refer to the below picture so you know how the plumbing of the Prodrive EBCS should be set-up. With the Prodrive EBCS you WILL NOT NEED TO USE ANY RESTRICTOR PILL!