First off you need to know if your state alows intake mods and if so you need a good intake with a carb #, and a bypass valve just stops some of the water from reaching the throttle prevent hydro lock(water in the engine). But dont go cheap buddy that sort of mod needs to be good, because we are talking about the frist thing that is going to go through your engine from start to finish. I would suggest a AEM intake pipe short ram so you dont have to worry about water reaching your engine(also AEM because it mounts great on your cars body preventing it from falling off) then with a K&N filter because well those filters are the best and that 1,000,000 mile warrenty cant be beat.
so yeah thats would be the absolutly the best thing

P.S DONT GO CHEAP ON THAT INTAKE MOD