springs & swaybars vs springs only (on gravel)

Does the choice of bars not come down to the driver? I remember reading something about the mini wrc in 2011. At the same event Kris Meeke used bars front and rear and Dani Sordo only used a rear bar. I remember there was a picture of dani ditch-hooking with the inside wheel at full droop and the outside was at roughly regular ride height. Still trying to find the article again...