Check the option parts that Ty Tessmann has been using at his XRAY XB4'21. Ty 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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#362250-G Composite Steering Block - Graphite
>>> I use the composite steering block because it gives more precise feel to my car
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#323355 Alu Multi Adjustable Rear Upright
>>> I use the alu rear upright to reduce flex and add durability to my car
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Composite Long Suspension Arm - Graphite
#362113-G Front Lower
#363113-G Rear Lower Right
#363123-G Rear Lower Left
>>> I use the long graphite suspension arms as they improve stability and increase precision
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#362574 Alu Steering Plate 2-Hole
>>> The alu steering plate adds rigidity and increases precision
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#364910-G Composite Gear Differential Case - Graphite
>>> Composite gear differential case increases consistency
