cold air intakes are better because they are longer and reach colder air away from the engine. Short Rams take in hot engine air. Go with an AEM CAI, Injen, Iceman, Volant, or the soon to be released Focus Central Intake.
they will both be SOMEWHAT similar at speed, but in town and not on the highway, you'll want the true CAI. the short ram will suck air from where the airbox sits now. sometime, drive your car for an hour, then park it and pop the hood. feel how hot it is over there (and all around). the true CAI will pull air from the foglight area (AEM) or by using the stock snorkle and add-on duct (Volant). im sure im forgetting some brands, but those are the two most debated around here. i have the volant and love every redlight! even my dad drove my car and asked me "what's giving that little engine that throaty sound?"