You'll want to. Slicks + less downforce + KERS (Kinetic Energy Recovery System) = awesome. The Kers is basically flywheel hooked up to the crank which stores all the energy usually lost in downshifting (it spins close to 200,000 rpm I believe) and then they use that power to shoot out of the corners or help on the straights. Should be nuts. Now that they don't use traction control it's even more entertaining.
In testing even the backmarkers were 4 seconds a lap quicker on slicks compared with the grooved tires they've been using.