well i can tell u if u are at 114 and u go back to 111 yes the idle will be choppier and you will have a better response from the car when u get on it, and it seems if your powerband is coming in later than expected chance is ur behind a tooth, as far as adjustable timing sets.....i dont like em, thats my personal opinion, too many variables of something going wrong, id say if this isnt a race car and just ur Fun weekend driver, then i would just make sure u have a good timing set now and advance the timing to get it back to normal and keep it that way, if your running a turbo/SC or N20 then i would say get an adjustable set seeing that youll be changing it from time to time, but then again everything is computer controller nowadays