The sound system will have a Gnome engine sound digitized from the real thing and tied to the esc so the RPMs match. There will also be a machine gun sound tied to the gear switch on the Tx, and there will be LEDs in the gun barrels so the flash matches the "pop pop pop." I don't have it installed yet, but that is next.

I don't know the CGyet, but I am assuming I will be OK because the sound system will come in about 16 oz, and its installed in the cowl. That is a good idea to open the firewall an push the battery through. It would move the battery 2 inches foward. That would move the CG forward 1/4" and every little bit helps. If I get into adding too much ballast, I will cut the firewall and go for it.

Another thing this thread helped on is I reversed the engine mount. This give more clearance of the engine against the dummy radial. I do not have to trim the dummy motor, and you do not have to reverse the shaft of the BL 46.

Thanks guys. I will post pictures as I progress.