I tried the RPM arms and went back to stock. They are way too flexy for track use with lots of grip, The handling is all over the place. Great for bashing, though. Can’t snap when you can virtually tie them into a knot!
I have the same truck and have tuned it quite extensively.
The stock shocks have plastic bodies and the bores are not uniform through the stroke. I ran a gauge up and down in there and there definitely are tight and loose areas.
Also, the pistons are way undersized. There’s a lot of oil...