I plan on doing this. Callaway is like an hour from where I live. Havent had a chance to do so yet. Moreso than ask them to build something for our car, I was thinking of asking for their input. As engineers who looked at the engine and decided how to improvie its performance, i wouldnt be surprised if they had other insights about "we tested it with a 3" downpipe and it showed great gains" or "a new intake will give you the most noticable gains".
Of course, due to legal crap with mazda they probably wouldnt even be able to tell me anything even if they DID have insight into the matter......but oh well - i do plan on stopping in sometime tho