Also been considering upgrading to a four stroke to match my 115 four stroke Merc pump. My main question is with finding tha sweet spot and maintaining consistant speed with a four stroke. I,ve beeb around several 9.9 Mercs (including RR's boat) and all seem to be so sensitive that there is constant adjustment of throttle. My 8 hp 2 stroke moves very smoothly through all ranges and is easy to hold speed without throttle changes. Also noticed what appeared to be more vibration transmitted to the boat than what my 2 stroke transmits. Any comments?