From what I am aware of, the term "Spirit of Competition" was first introduced/associated with the Pajero, by Mitsubishi, in the Dakar Series.
It was plastered on their Pajero and continued to be featured prominently throughout the model changes (which included around 7 stints in the Paj-Evo) up until the Series was called off recently.
As the Legend grew, the decals slowly started to appear on the Evo's and continue to be made available for those that way inclined.
I think they are OK but it depends on the colour of the car and it's intended use really.
The only reason I would put decals on a car is if payment is involved...........Unless it's an evoowners decal of course!
El