Anet A8 40x40x20 Extruder Fan Mod

I had to switch the blower fan which my Anet A8 came with using the 40mm fan for the stepper.
I couldn't make something complicated but I built the 40mm adapter found on thingiverse by ChineseStar.

I've then ordered a better fan (40x40x20 Akasa, better airflow than the 40x40x10 and quite silent (27 db)) and I've decided to fix all the small problems that came with the original design.

My piece came a little bit tilted from the print as air flow was not optimised, so a small part in the f