NIC Tuning Parameters

I have been researching a number of NIC hardware parameters to optimize a
desktop to perform as a firewall, for both throughput and a large number of
connections. Below are these parameters:

Receive Buffers
Coalesce Buffers
Transmit Descriptors
Receive Descriptors
Transmit Control Blocks

The firewall will contain 4 network cards, 2 cards accessing DMZ's, 1 card
for External Access the other for Internal Access. The internet access runs
at 10MB Half Duplex and each other NIC is connected to 100MB Full Duplex.
The above settings are reference in a performance tuning guide for
Checkpoint, and are configurable through the Intel NIC Driver.

I understand that the default parameters would function, however I am
justifying researching this information on the basis that Desktop NIC Driver
Parameters are configure based on their purpose. Since the firewall will be
acting more closely as a router as oppose to performing as a workstation, I
would think that possibly that Desktop NIC Driver parameters need to be
'tweak' to perform as a router. (Just using router as an example of a
network device that may have varying settings).

Does anyone have any recommendations or experiences regarding the above
settings? Any recommendations regarding where to find information for these
settings? Or any other NIC tunable parameter that someone has tweak which
has played a significant impact on performance?

Thanks,
Dave