Just one suggestion why dont u have the whole case fan area cut out

grab a piece of acrylic and cut the 12cm fan hole

Screw the acrylic back to the case with nut and bolt or rivert it ....

make sure to paint the acrylic black or just get a one in black color....

Applicable to both front and back blowhole ......it would make ur mod to perfection ....

Just curious why dont u have ur sleeve color change to red ... it would match the color of the PCB board for both mobo and gc.....

since u visited the eletronic shop... i would recommend u to grab some molex connector for custom cable for ur HDD that is kind of a lot there....

u could custom the length so that it has least exessive cable... it make it cleaner .....

further more with the zip tie base u could have some wires stay close to the case rather than hanging around ....

just suggestion only ....