FWIW buying the RC'2s is about 30% or more of the value of the kit, IMHO.
I bought the kit from Jim a couple of years ago with the 300m rears and the RC2s and the adjustable shocks make all the difference in the world. The kit is built super stout you won't have a problem with the arms, ever. Get the good shocks and dial it in to your style of riding.
My wife, 2 years later still thinks it was the best $ we ever spent on the machine. Somewhere back in this section is my ride report, if you are on the fence go read it...you won't be on the fence anymore.