The Mast Mounted
Wheel Antenna increases your flying range and importantly will
drastically reduce irregular video dropouts when the drone is rotated.
Typical distance increase is around 33% to 50%. You most likely will experience even better performance according to your control device. Critical for FPV flight, you will experience far less video drop outs when the drone is rotated at a distance.
Galaxy Nexus Phone: 120 Meters (400 feet).
Nexus 7 Tablet: 215 Meters (700 feet)
iOS Device - extended range varies with various models
Modifying the AR Drone to use a traditional RC transmit-controller is a popular modification. Physical joysticks can enable additional flight confidence. HOWEVER, an RC Mod will not add one extra meter of downrange distance if you are flying via FPV since you are still depending on the WiFi for video downlink.
For ones that simply like flying traditional RC, an RC Mod will put those familiar joysticks in your hands so you can enjoy flying within your close range line of sight.
For deep downrange FPV flight:
If your objectives include breaking the bonds of close range line of sight flight, then consider focusing your efforts adding a WiFi Range Extender setup. Also, use a game controller with your control device for physical joystick control which can improve your flight confidence. The overall cost of ownership is typically less than an RC Mod (including RC transmit-controller).
If you seek deeper downrange flights, then stay with all WiFi control and challenge yourself to Go For It !
Warning... once you obtain your first deep down range flight, desire for more can occur.