You might want to also check out
GT Motoring: High quality performance parts supplier also. They are in Crystal Lake and are more focused on the 370z car. Please don't get me wrong SP and AMS rock! Martin at AMS tuned my old S14 240sx (400hp YAHOO!!) and I have a lot of supra friend that love SP. The guys at GT Motoring really know the car plus getting back from Japan and talking to companies like Amuse, Zele as a host of others. They can really point you towards what you are looking for. They have really helped me in what I am looking for.