Don't add a fan to it - it's a waste of time, not to mention the electrical noise you might introduce to the line. Wall mount it and it will be solid, I have had all the versions, all have been wall mounted and never had any issues.
BT Infinity
ROUTER:-Netgear WNDR37AV
JDSU Stats
Attainable 105977D 38659U
Sync 79999D 20000U
Attenuation: 5.4 SNR: Down 13.1 Up 24.3
Line Length 160meters