If you do a canister exhaust, or even a muffler, but get it back under the wing (that's what I'm doing) the actual NOSE moment arm won't be outside design parameters that they state, because the ST2300 isn't more than the YS 110 with muffler. Or at least it's pretty close. I won't be concerned about that, and was a bit tongue in cheek about battery in the tail. It may have to go to the rear of the wing area or soemthing, but I doubt much more than that.

Regards the servos/hardware....yes on the "stock hardware". It's not too bad, really, but the angle does put things in a bit of a bind on the elevator pull-pull (see other info about "Ackerman in Pull-pull"). The solution is the DuBro extended control take offs so that the clevis attach point is over the hinge line. That's probably what I'll do on both, now that more non-flying time is upon us.

Servos - I have JR 8231's on Ailerons and elevator, and JR8411SA on the rudder. Was using a Hitec HS 55 on throttle, but since I need more tail weight, I'm installing a standard JR something (probably a 4131 I've got laying around) in the designed throttle servo location.