I had no major issues running a ballistic 17.5 with a tekin rs. I am running a non-digital servo though.
Only issue I had was trying to run 0 timing on the motor. I was able to run 0 on my redline 17.5 but not on the ballistic (the motor seemed gutless with less than N timing). The motor had lots of power and stayed around 160 degrees once I set the timing to N (same RS settings my redline had: boost 50, turbo 10, turbo timing .4, turbo ramp 3, 2700 - 7000).