I designed this to meet the following criteria
1)Make use of the existing holes, threads, and bolts
2)Refrain from defacing the original design so reversion is possible
3)Keep the OEM stock air delivery method
4)Make larger in diameter and height
5)Accommodate for brass inserts for a clean flush look
6)Bigger air ducts
7)long swinging curves with least obstructions
8) M2 (Biqu hole size) to M3 (4020 fan size)

Your choice whether to use brass inserts or not. I made the holes 3.8mm x 5.8mm. They are tight. The air duct, printed flat does not need any supports. The left and right braces do. BE CAREFUL printing these together. MAKE SURE there are no supports in the air duct. It can be tedious putting in "NO SUPPORT" blocks in the airduct if printed together.