First MAJOR update needed is the slipper and diff box’s, luckily arrma actually provide the upgrade path for this and alot of the other upgrades
https://www.modelsport.co.uk/product/arrma-metal-slipper-power-module-boost-box-1351450
https://www.modelsport.co.uk/product/arrma-metal-diff-boost-box-1351448
17mm hex currently running both 12mm and 14mm
stearing rack aluminum
https://www.modelsport.co.uk/product/arrma-aluminum-steering-rack-1338668
motor and engine mount
https://www.modelsport.co.uk/product/hobbywing-xerun-axe550-r2-3300kv-1334728
RPM arms