Hi Furrynutz.
After doing several tests with the cooler pad, I can tell that at least, the reported issues in this post are gone

so it seems that DIR-827 has a heat issue when doing several tasks or using max wifi speed.
I've not enabled the 5 GHZ band and other features like the USB media server.
I've downloaded like 8 GB at full speed without loosing my WiFi connection, the issue that randomly the speeds drop down to 10Kbs or lower remain, but the main issue of loosing connectivity is gone.
It's a shame that DLink has a faulty router with the DIR-827