I don't know about the Spider but just had to swap out the ABS in My Slingshot
The ABS system in the Slingshot is a stock GM part and designed for 4 wheels
One port is capped off with a bleeder
It works thru its own portion of the ECU. I do not see any regulators but I an sure it is tied into the 3 wheel speed sensors
Thats I I got!
Hope you post the final project here