I traded my 2000 GT 5-speed for 2005 GT 5-speed, both completely stock. I don't feel any difference (seat of the pants) acceleration difference between the two cars. Has any body else noticed this?

The tune makes these cars throttle response amazing! A CAI/tuner combo could run you about $600(depending on what/who you go with). By far that could be the best cost effective mod to these S197s. Do a search for CAI and tuners on here and you could be reading for hours!!!!!