Nice work! I love the Y-pipe, I'm betting that will produce some decent numbers all by itself.

I am wondering what you're going to do with the sensor that went in the original Y-pipe, though.

And one thing to consider if you're going to make these for customers:
Make the angle of upper arms of the Y-pipe adjustable or flexible. That way you can match them up perfectly with your intake manifolds regardless of what size spaces you use. This would also allow the use of spacers between the engine and the bottom of the intercooler.