Gas production and dissipation use to be on old brakes due to the compounds they where made from. Modern pad materials don't do this. It's one of them things people still go on and on about without realizing times have changed.
As said grooved discs do not really benifit you much and are a waste off money IMO. Drilled are a complete waste, I have seen so many crack under hard use.
The feraddo pads are the best IMO but they do cost a bit which is the down side, but they will not disappoint. I have never been a fan off the pink, red, yellow, purple green stuff never understood what the hell was the hype apart from the food coloring. Either go stock or go all out, I am running a Mintex setup at the moment which seems a slight improvement and a better bite, but I can still smoke and bake the pads under heavy driving, but for n0bbing around and normal use they are spot on.