Here are the option parts which I used at the EOS and finish overall in the 4th place in the first year with the new XB2.

#322510 Alu Steering Arms
- more steering, more precise

#322314 Brass Front Lower Arm Mount 23°/29° Kick-Up
- more steering and rotation

#323120-G Composite Suspension Arms Rear Lower Left
#323110-G Composite Suspension Arms Rear Lower Right
#322110-G Composite Suspension Arms Front Lower
- "must have" part on high grip carpet, less flip, easier to drive, more corner speed

#323041 Alu Rear Roll-Center Holder
- better flex.

#323351 Alu Rear Upright
- more rotation, useful on carpets

#326110 Graphite Battery Strap 2.2mm
- more rotation, turn faster in corners

#365471-K Alu Drive Shaft Safety Collar - Black (3)
- for long durability

Let me know how these option parts work for you and have fun on a track!