To unlock this you need to come at least 2nd
overall in every event through all 4 tiers, which can be achievement on
any difficulty. By overall i mean for events with more than one race you can come 2nd overall on points.
Highly advised to try for 1st to unlock the GOLD! achievement also.For me i stuck with the beginner cars for most events as for some reason a slower car gave easier AI, so here is what i used.
Rampage/8 Ball/Knock Out/Hard Target events:
Jupiter Del Rio or Lafayette EulogyRace off/Domination/Eliminator events:
Beliveau MeteorHead 2 Head/Smash Hunter/Trick Rush events
Ford Fiesta H.F.H.V.Those are only suggestions to what car to use, use what you are comfortable with.
Use your boost wisely and where possible spin your opponents out.
This will unlock bronze also.
The Bronze! achievement in DiRT Showdown worth 49 pointsComplete the Showdown Tour with at least a Bronze in every event