To be totally honest, NO, since you are not going big HP you wont have any problems. You will find that with your setup the pro's will far outweigh the con's. With a following sea you will see a big difference in pitch attitude(for the better.) Essentially a longer boat. Remember that the farther you can get the propulsion set back from the trailing edge the better.

Just ask Macojoe. He doesnt have the fuel in the belly but he has fuel in there somewhere. He absolutely swears by his conversion.

My $.02

C.