Everyone here is guiding you the right way...RUN away from any shop that says they can get you that kind of power with a tune. Can go the full bolt on route with tune etc. but if you plan on wanting big power you need to go with a supercharger. If you plan on going with a supercharger in the near future then a tune would probably be a waste. I had a non FI m3 for a few years and it kept me entertained
Of course this one is a totally different animal and I am really enjoying the Active kit. I have heard great things about the tune mentioned in this thread and the Evolve tune as well. Do some searching and you'll find tons of opinions but these two tunes specifically stick out in my memory.
Enjoy!