They might not have trim issues, but the look is certainly off :-). The system will work perfectly....at 1 certain airspeed, with 1 certain throttle setting. Everything else will cause momentums. It's easily flyable from the looks, nothing serious, but from the ground you can see that something is "wrong". If you can live with that, go ahead, it certainly saves money :-). I'd put in a bifurcated pipe or twins....

As to the "overpowering"....well, you can always throttle back or even limit rpm in the ecu. This will give you better efficency on most engine types.....there are no overpowered airplanes, there are only pilots working the throttle stick to agressively ;-)

By the way, do you have pictures of the large A-6? Just out of curiosity ;-)