BBK is 1mm larger than stock, CFM is 2mm larger.
If that convinces you to spend $250 so be it. I don't think it's worth it.
Stock: 20.5735 in^2
BBK: 21.2114 in^2 (0.6379 in^2 larger than stock)
CFM: 21.8591 in^2 (0.6477 in^2 larger than BBK)
Don't "think outside the box".
There is no box.
Do it correct, or do it twice.