The lower pressure spring allows you to run less boost in order to help keep traction in 1 st and second gear especially where traction would normally be the biggest issue on say an 8 or 10 psi spring .The 4 port allows for both better spool time and the ability to run the lower wg spring and still be able to make the desired amount of boost up top .I have not yet installed mine but will be in the near future .I am looking forward to the added benefits of both the lower springs and the 4 port solenoid .Make sure you share that dyno graph for us to see once your tuned.