For those who don't already know, the FMS "Mini" warbirds usually have a piece of metal weight buried somewhere in the nose section to balance the aircraft, as the stock bell-type motor used for these models are too light to achieve the correct CG. Even with this arrangement, most will find these models to have tail-heavy tendency.
Having some time on my hands, I recently performed the "surgery" to remove the metal weight, stock plastic firewall and motor from my A1 Skyraider, replacing the stock motor with an EMax outrunner weighing around 80g+ which adequately balances the aircraft without further need of the metal weight. No more carrying useless weight around... it is now part of the power!
Mounting the new outrunner required careful trimming of the nose section and construction of plywood firewall, in order to get the correct measurement to fit the nose cowl. Final result in the photos below, and safely test-flown