Will the use of one or the other HWIC-APs allow for access speeds of 108Mbs connections with a wireless G client?
Sadly no. The number 108Mbs is the combinaton of 802.11g and 802.11a data rates, and with the subtraction due to overhead the actual throughput is much lower. Have a look;
Approximate Throughput Comparison for 802.11a, 802.11b, and 802.11g
802.11b Data Rate (Mbps)=11 Approximate Throughput (Mbps)=6
802.11g (no 802.11b clients in cell) Data Rate (Mbps)=54 Approximate Throughput (Mbps)=22
802.11a Data Rate (Mbps)=54 Approximate Throughput (Mbps)=25
From this great doc;
Hope this helps!