Check the option parts that EOS Champion Bruno Coelho from Portugal has been using at his XRAY XB4'21. Bruno explains also the benefit of each part, for which track conditions they should be used and what performance improvement you will experience.
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Alu Multi Adjustable Rear Upright & Hub Plate #323355 Rear Upright #323381 Hub Plate
>>> The alu multi adjustable rear upright and hub plate for it is a must have for carpet and astro as it improves rotation and handling.