Advice on choosing a 300N router for 76Mbps VDSL

Hello all :)

Iam helping a friend find a suitable router for a FTTC VDSL connection running at 76Mbps over wi-fi, he has a 300N class wi-fi card in his laptop and would like to get the best wi-fi router possible to sync with the VDSL modem to give him the 76Mbps speeds throughout his home..

Iam under the impression that most 300N class routers in 150N (20Mhz mode) are good for a MAX of 60Mbps and average 40Mbps so I thought that therefore with the router and laptop running in 300N (40Mhz) mode these figures (in theory) should double to 120Mbps max and 80Mbps average, which means a 300N setup should be good for 76Mbps throughput in an average sized home...in theory!! - but then looking at some of the test results I see on here it seems switching from 20Mhz to 40Mhz does almost nothing??

does he have to upgrade his laptop card (again) to dual-band 450/600/750/900 class spec?

so...does anyone know of a 300N class router that is reknown for its signal strength and throughput-per-distance that could support 76Mbps throughout a regular 2up2down home? if 300N on its own is not enough, can anyone advise of a dual-band router and one that has a Mini-PCI-E card available for laptops too...

thanks :)