Closing top case or not?

Since I'm still waiting for my cpu I thought about optimising my case a bit.
Right now I have two pillows where my rad rests. Would it be recommended to close the surroundings with cardboard and ducttape so only the 2 fans won't be covered? Or is it better this way?

I guess you could duct it... might give you 1-2°C drop or rise in temps of whatever';s in your WC loop.

your case temps might be a tad higher though

if i may ask. where did the top of the case go?

because if you only remove the top of the case to fit the radiator and fans, you can just cut 2 120mm fan holes in the top of the case and create good airflow and looks.

The top of the case is lying right next to me here, maybe in some distant future i'll cut holes in it (have to buy dremel first...). Since the PC is going under the desk where you barely see it, I don't mind the looks for now.
For the time being I just made this duct which easily comes off so I can just see whether it helps cpu temp's or not.

Can anyone say Ghetto get some acrylic from Home Depot measure where the 120MM fanholes go tell them and they will cut it for you then problem solved....bring it home attach a couple of 120 MM led fans to swap out the ones you have and have one hell of a night light.