As long as you get it on there the right way, torque everything to spec, adjust your belt tensions to about where they were when you started, and make sure the belts are in good working order, you shouldn't have any problems. If anything, it'll be better for your engine because it will be working slightly less hard to move things. The dampening associated with the crank pulley isn't really a huge issue with our cars because of the way the engines were designed. I think you'll be pretty surprised at how heavy the stock pulley is compared to the aftermarket lightweight piece.
07 WRX (Albins 5MT + Blouch 20G)
Jorge Carrillo Tuned (365 whp/340 wtq)