Dodge: 2002 dodge neon sxt

i am looking to get a k and n cold air intake for my car. it clamis it
increases hoarseower 5-15. does it really give you 15 hoarsepower. also
it is real low so is their a chance a sucking up water and hydrolocking
the engine. and would a by pass valve that prevent water suck up rob hp
for the intake.