Here is your checklist.

Drop the washer fluid,
remove swaybars,
fit some softer rear suspension,
remove the stereo head unit,
paint the tires with nitto traction compound,
fit welded rear diff,
fold the mirrors in,
tape up all the panel gaps (just not the drivers door),
give the car a pressure clean underneath to remove excess dirt,
short shift 1st,
use a smaller car battery,
remove rear spoiler,
remove wiper blades,
remove a/c belt,
run only the park lights during the race,
neutral all the camber/toe,
lightweight rims/tires,
lightened flywheel/clutch,
More boost.

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Long live the WRC