I experienced this same issue using the Dev build this past week. I have yet to use the new 1.3 release, but I will tell you what caused the same lag for me - especially while pitching - the "Trajectories" mod.
I isolated the problem down to Trajectories (my other 40 mods work fine with FAR without Trajectories). I removed the Trajectories mod and FAR works flawlessly. I will go test FAR for 1.3 this evening and will come back to post should the issue persist without Trajectories. Hopefully this is an appropriate place to share my experience with this issue (first post here).