If you can spring for a dual intake, I would suggest that. Needswings (Performance auto parts & aftermarket auto accessories for your car, specializing SRT4, Crossfire SRT6, SLK32, C32 AMG, VR-4) offers a nice intake. Also, larger fuel injectors may help out as well (although some may say that these are not needed with an auto depending on how you drive). When I am driving more aggressively with my auto, I tend to use the Autostick more and keep the RPMs higher. These larger fuel injectors will help with that.