Check the option parts that Multiple Czech National Champion and EOS podium finisher Max Gotz has been using at his XRAY XB4'21. Max explains also the benefit of each part, for which track conditions they should be used and what performance improvement you will experience
Adjustable Drive Axle & Alu Shim #325341 Drive Axle LB #325390 Shim
>>> The adjustable drive axle is used to always match drive shaft length with the width of the car.
Composite C-Hubs 6° #362211 Right #362221 Left
>>> Less caster makes the car less stable on high speed but it makes the car stop less and improve the handling.