These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Car Tiers - Throughout all of the series, the cars have been organised according to some common defining feature: 4WD class cars are obviously 4WD, FWD cars are obviously FWD, and so on.
Di RT 2 abolished this practice by instead seperating the cars into their respective event class (rally, rallycross, Raid T1 etc.). However, cars could be upgraded or downgraded into Rookie, Pro or All-Star classes.
Di RT 3 seperated the cars into their eras; such as 60's, 70's, 80's and so on.
Di RT Showdown utilises an upgrade system, meaning players take all cars (with the exception of the Gymkhana cars) from D class to A class.
Tear Jerker: Beating the Colin McRae challenge in Di RT 2 treats the player to a short tribute to Colin's rally career.