Changed my plugs with Denso Iridium Racing Plugs... Pain in the as* to do unless you have midget hands... And they really don't make much of a difference...

If you don't know, your throttle is "drive by wire" it does not have a direct linkage to the injectors... The computer learns your driving habits and adjusts the ECU accordingly. In other words, if you drive like an old lady most of the time, the car thinks you're an old lady all the time... So when you want to get on it... The car still thinks you're that old lady!

What I would recommend, start driving more aggressively for a few days and you should notice a slight improvement in throttle response... Also, open-up your airflow with one of the aftermarket kits (SASKINS dual intake recommended) then put a less restrictive exhaust system on... And if you really want to get the seat of the pants feel from your car, do all of the above and then have the car chipped and run 100 octane fuel in it...

All in all about $1,500 and now you've got a car that should put 235hp to the flywheel...

As far as the EVOSport Underdrive pulleys, I can't see the advantage... Granted they are only a few hundred $, but I still have yet to get a good explanation as to how or why they would increase HP... only thing I can see is that they would lower the output of your alternator... Not very helpful IMO...