Hi Carlos,
I had a Vararam installed several months ago and it definitely wakes up the performance around 40-45 mph. Other popular ones are the Callaway Honker and the Ligenfelter CAI. I've heard from several folks that the Ligenfelter can be difficult when doing the filter cleaning.
I'm sure Antivenom suggestion is excellent as well. Vararam purchase plus install ran about 350.00 or so. Good luck. Let me know how it goes.