as you modify the way air comes into an engine, your also modifying the powerband of the motor. so in all actuality, youre not really losing that power, its just getting allocated to the top of the powerband i.e. that new 10-15 horses you just picked up. that extra air is allowing the engine to rev a little freer or work less harder if you will. you should also put a better exhaust system on too to complimate the intake. there is probably no way to keep the low end power when adding the cai unless some sort of restriction for low rpm is devised. i would just live with it. your not using a racing motor so the loss is going to be negligable. more of a seat of the pants feel except in reverse i guess.
one of the systems that includes an aftermarket air box might not be felt as much as say the nismo or k and n system, but then the only real gain to it would be the less constricted airtube from the box to the throttle body. your best bet then is to buy the k and n drop in filter, and possibly the stock airbox mod. ive done it to mine and felt a little bit to kick in the seat increase, but not a lot. enough to be noticable. a little louder too. remember, all these cai's make theyre increases at 5000+ rpm. i dont know about you, but i hardly ever go above 3000