I kinda bashed several of them. I have never removed any span though. Mostly cleaning up the nose, rimoving the cheeks, and blending the fuse from the firewall to the spinner, making it a smooth transition. Also I normally add elliptical wingtips, and use different aileron stock for more control area. Last, I enlarged the rudder and elevators and made them more like an extra. Lotsa throw, and very strong servos (on 6 volts) Does well with the ST-G90, but I have used OS 91 Surpass and it's probably the best combo. These mods really wake up the model, but I think the single best mod is the nose.
These are my honest observations from bashing the 4 Star series over the past several years. Works well with the Bingo/Big Bingo series as well. By far the best of these is the 4 Star 120 with the above mods powered with a Moki 1.8 Get back and watchis!!!!