I was looking at Kubota's Canadian web site and saw the new m9960 has as a option a 540/540E pto. I assume they will offer this in the USA? Also what are the drawbacks to the tier4 engines? I kinda like the idea of better fuel economy and with all that muffler they might be more quiet. Anyone that runs the tier 4 Kubota 230 cubic inch that can comment on the sound and how the engine performs?