Just my thoughts
I have just purchased what should be a similar unit on ebay from moparmaniac. Which he is calling Coolertubz. He has a buy it now unit for $180. He has 1stgen, 12v,and 24v. I like it. However, this seems like a better deal. If the person that builds these is using polished ss and cleans the welds up. I spent about an hour and a half cleaning the weld up inside of mine. The stock intake on my 12v at the smallest point is 2. 25" square. That's about 5. 06sqin. The grid heater is the next smallest point @ around 8sqin. The I. D. of mine is 2. 75". The area is 8. 635squin . The O. D. is 3" which matches the boot. You will also need some sort of seem that will help hold on the boot so it will stay on when boost is applied.
Hopefully I have helped.
There seemed to be a slight increase in spoolup?
* The area of a circle can be found by multiplying pi ¶ (which is equal to 3. 14) by the square of the radius
* If a circle has a radius of 4, its area is 3. 14*4*4=50. 24
* If you know the diameter, the radius is 1/2 as large.