You know one other thing that you may want to try that gave me AWESOME response at the throttle...
I went aheand and broke down and paid the $15 per spark plug and put in the new iridium plug from NipponDenso. You can get them at your local AutoZone or any other major parts store. Aside from a very obvious increase in throttle response and HP, they advertise increase fuel efficiency. On top of all of that, they are good for 1,000,000 miles, so you never have to change your plugs again.
Just a thought.