Joe, I used the range device on my 2013 SS L99 with Dynamax axle back. Had no issues. I ended up changing the front pipe to an LS3 pipe and combined with my axle back the sound was much better. I eventually got a tune from
dynosteve@rdpmotorsport.com. Night and day difference in performance now. The LS3 pipe does not have the giant suitcase resonator in the middle and is much lighter....you can get the LS3 pipe for next to nothing. Good luck, Bill