Here is a shop that does nothing but tune Z cars and try and put together and sell quality (yes quality) performance products to help us (The Z community) get the most out of our cars. I am overly happy with my Ashpec ecu upgrades.
I remember when Stillen was the only thing out there when I got my first 300zx (before it was stolen) and now there are numerous shops to aid in stepping up the HP numbers.
People weren't bitching about Stillen back then. Now look at what they say.