Not sure which country you are in but in the 5GHZ spectrum not all channels are available in a given country. Part of the 802.11a/n 5GHz spectrum overlaps with radar and therefor the channles avaialble depend on the country you are located in. See http://en.wikipedia.org/wiki/IEEE_802.11h-2003 and http://en.wikipedia.org/wiki/List_of_WLAN_channels#5.C2.A0GHz_.28802.11a.2Fh.2Fj.2Fn.29
According to the specs you can connect on 40 Mhz channels:149+1, 153-1, 157+1,161-1 (where +1 means above and -1 means below). No other combinations are allowed based on the specs.
All Intel 11n wireless adapters support 40 Mhz connection at the channel combination mentioned above.
So, boil down to the bottom, why regulatory think 153+1, 157-1 is illegal? I don't think this is caused by hardware.
