Considering most TC-9 based drivers are for SQ purposes I would say the cooling provisions are more than adequate taking into account the nearly 1.5" diameter pole vent, especially when mounted to a basket with large windows under the spider. I understand that blocking that vent will give you greater air velocity over the coil in the gap area but that comes at the cost of a substantial amount of turbulence noise being generated as well as restricted cone movement, not to mention a shift in parameters, should everything else remain static.