2.5" piping and development of a set of intercoolers with 2.5" inlets and outlets that it was clear whether or not it would be beneficial. Before that, most people thought it was really a waste of money - saying there would be no power gain and would be laggier due to the extra volume. If you look at the dyno comparisons you'll find that to be exactly opposite of the truth.
I'm sure there will be others to Rob and Duplicate this product eventually and probably put it out for less money. But for the money, the materials, manufacturing processes, and fitment you get out of this kit I am offering is the best deal you will find.