Made an upgrade of the 9398 with XL motors and gave it 30% more additional parts. This is my MK2 version as my first upgrade was not as successful. Also it uses
LEGO Technic 4X4 Crawler (9398) Building Kit 1327 Pcs Truck Lego Set | eBay
Ultimate upgrade for the 9398 4x4 crawler with pendulum steering (no servo needed). I also made a pendulum steering file in the rebrickable link you can download and have a closer look
Lego Technic 9398 Rock Crawler Preview | The Lego Car Blog