Kong, if you have a Merc/Mariner 15 2 stroke then that is IMHO the best 2 stroke for the boat - the lightest and the best operation with one hand tilt/trim and tiller gears. Very well made and reliable. Affordable and you'll not lose a penny come sale time. A bit thirsty is the only downside.
You'll need a 25/30mm block on the Aerotec and maybe fashion an anti-splash deflector - not sure if it's on this topic but there are loads of pics and how to on these in various discussions on here for these.
Because the BAT hull continues in it's unique shape to the transom instead of flattening off it channels all the water to the aft centre and combined with the Merc/Mariner leg design it hits this and goes up - a simple L shaped deflector attached to the lower two transom plate screws stops it.
This is the final one still going strong two years on, other attempts in links below:
http://www.rib.net/forum/f50/rigging...tml#post715124
http://www.rib.net/forum/f50/bombard...tml#post686813
http://www.rib.net/forum/f50/bombard...tml#post687789