I have a 1987 S4 TII that I am currently connecting to a ms3x. One thing I am concerned about.

Since the EFI harness goes away, so does the pins to the check valve (for the switching actuator). According to other posts, these pins send 12 volts after about 2700rpm, and then the switching actuator changes to twin scroll. What wire would I use to connect this, and would I just connect the other side to a ground? Another option is to disconnect it completely or wire it open, what do you all do.
switching actuator question - RX7Club.com - Mazda RX7 Forum

 

the stock setup is power-> solenoid -> ecu -> ground. and i think the stock thing just switches by rpm, so you can use an switch setting in the ecu.