The Motorflote is completely flat fronted, at least the Springer does have a more rounded bow. A Springer does try and get up on the plane, a Motorflote will just start to porpoise if power is increased, the porpoising will just get worse the faster you try and go with it.
I don't think there's room to get a bigger motor in, I'll know for sure when the kit arrives later this week...if there is a chance of squeezing one of Mr Action's 550's in, then I will, but looking at the drawings it will be tight. The only other choice is to go brushless, I do have a brushless motor that Andy recommended, c/w the matching esc and a lipo, so I'll check that out when the kit arrives.
Rich
Pic shows size comparision between brushed and brushless set ups.