Elevators limited to +/- 13 degrees
Remove rudder input and couple to aileron input
Remove rudder steering and couple to aileron input
Remove flaps 
Remove lift from speedbrakes.  Ercoupe windows will open in flight, the speedbrake will simulate this.

Adjust weights based on www.ercoupe.net/ads/Log-94106.pdf
Adjusted locations of all fdm items based on the type certificate and model measurements

Added third fuel tank

Stiffened nose gear by 50% based on model observations

Adjusted drag due to speed brake deflection to yield a 10 mph drop in speed during stable flight at 100 mph.