I ride a mtn bike that I "souped up" for the road, meaning I put smooth tires on it. Instantly gave me 2 mph advantage. I definitely recommend putting smooth tires on the bike, since that's the easiest way to gain speed with your type of bike. With a hybrid (or mtn bike) you're already upright, so you lose a lot of aerodynamics with the position. Being upright is the biggest detriment to higher avg speed, but if you are more comfortable being upright, then that's more important to you than going faster. If going faster was your top concern, then you'd have a light road bike. So it's all a matter of preference. I, for one, prefer the comfort of a mountain bike, mine is light and has loads of gears for the crazy hills we have here. The best way for me to increase speed was to put the slicks on.