Some recommended but not necessary option parts:
TM507251 Option Part - E4RS II EVO - 3D Flex System
Recommended for motors under 10.5, to avoid belt tension problems with maximum flex setting.
TM507252 Option Part - E4RSII EVO - Middle Flex Post
To fine tune the flex, interesting on high grip and/or carpet tracks.
TM507253 Option Part - E4RSII EVO - Upper Plate 2.3mm
TM507254 Option Part - E4RSII EVO - Upper Plate 2.5mm
To fine tune the flex, interesting on high grip and/or carpet tracks.
TM507257 Option Part - E4RSII / E4RSII EVO - Front Anti Roll Bar 1.2mm
TM507258 Option Part - E4RSII / E4RSII EVO - Front Anti Roll Bar 1.3mm
TM507259 Option Part - E4RSII / E4RSII EVO - Front Anti Roll Bar 1.5mm
TM507260 Option Part - E4RSII / E4RSII EVO - Front Anti Roll Bar 1.6mm
TM507261 Option Part - E4RSII EVO - Rear Anti Roll Bar 1.1mm
TM507262 Option Part - E4RSII EVO - Rear Anti Roll Bar 1.3mm
TM507263 Option Part - E4RSII EVO - Rear Anti Roll Bar 1.4mm
To optimize the roll control.
TM507264 Option Part - E4RSII / E4RSII EVO - Carbon Fiber Motor Guard
Interesting to laterally protect the motor.
TM507265 Option Part - E4RSII / E4RSII EVO - Carbon Fiber Upper Bumper Mount
To make your stand friends jealous
TM507266 Option Part - E4RSII / E4RSII EVO - Belt Tensioner Set
Interesting to control the front belt movements.
TM507271 Option Part - E4RSII / E4RSII EVO - Aluminium 7075 Drive Shaft (2)
To reduce the rotating masses - be care if used with high power motors.
TM507278 Option Part - E4RSII / E4RSII EVO - Aluminium Lower Spring Mount (4)
Interesting to better control the springs.
TM507279 Option Part - E4RSII / E4RSII EVO - Aluminium 7075 - Battery Mount
For people who prefer a strongest battery guidance.
TM507286 Option Part - E4RSII / E4RSII EVO - Aluminium Clamp Type Hex Wheel Hub -0.75mm (4 pcs)
TM507287 Option Part - E4RSII / E4RSII EVO - Aluminium Clamp Type Hex Wheel Hub +0.75mm (4 pcs)
TM507288 Option Part - E4RSII / E4RSII EVO - Aluminium Clamp Type Hex Wheel Hub +1.50mm (4 pcs)
To set the track width (outboard).
TM507289 Option Part - E4RSII / E4RSII EVO - 20T 7075 Aluminium Pulley
For powerfull motors.
Here are all the Team Magic E4RS II EVO optional parts:
http://www.teammagicrc.net/products....ption+part+evo Some are more designed for your pleasure than for a real performance benefits (I think about aluminium uprights).