Im looking for a new chainsaw. There seems to be available from reputable manufactures like Husqvarna only models with autotune carburetor (555, 560xp). I would need a saw 60cc for forestry logging and also for log building work. As Im understood the autotune is working only in two modes: idle and full speed. But i would need medium speed (half rpm) on log buliding jobs. Also no need for rev boost, because i would like to change saw chainspeed comfortably. So for this case i have to set aside 560xp and prefer 555 ?! But the main question: does autotune saws enable smoothly variable chainspeed (low-medium-high) ? I have got some answer from dealer, that yes its possible, but theres a need to adjust the autotune carburator after some working time or something..