Bill the Red and Green Spring are a great combo on Eddie's motor's for 1/12th scale.
If the track is more spread out and faster you might even try a Green on Both Sides.
I did the same thing to one of the Motor's Eddie Sent me and it's a screamer.Im actually at Green/Green due to our track being 100x60 and pretty fast right now.If it tightens up I may have to go back to red but for now I dont see it.
I also Took an exacto blade and put the tip in the VERY center of the - side brush.Start twisting the blade into the brush making a Hole.
You Probally wont notice alot but it did help on brush wear and Motor Temp just a tad bit.
You will notice you will get MORE runtime when switching to softer springs due to Effic gains.
Goodluck running 1/12th with the monster.Eddie makes some VERY NICE motor's.
When cleaning the motor remeber to clean the brush hoods as well when cleaning.