Question : Problem: 10/100 Ethernet on a Cisco 2500 series?

I've got a Cisco 2514 (two AUI ports, two high-speed serial ports). I use it mainly as a firewall (implementing NAT), and it's connected in between my 10/100 switch (my internal network) and another 10/100 switch (the DMZ) which hosts servers. The DMZ switch uplinks to my DSL modem. Currently, I'm using the two AUI ports with 10BT ethernet tranceivers. My switch is 10/100, and so is my DSL modem. I have two questions:

1) Would it make a difference in speed under any application (web surfing, file transfers between servers and workstations locally, etc.) if the data passing through the Cisco router were 100 mbps, and

2) Is it possible (or how would I) pass data through the router at 100 mbps (without buying a Cisco switch or another router). Are there 10/100 AUI tranceivers? Are there tranceivers for the serial ports?

To clarify my network setup:

(Workstations) => [10/100 Switch] => [Cisco 2514 (10mbps)] => [10/100 Switch] => (Servers) => DSL Modem

Thanks.

Answer : Problem: 10/100 Ethernet on a Cisco 2500 series?

I think thomaswilliams is saying the servers are in the DMZ switch, not the local workstation switch.  Therefore, from a workstation through the router to the DMZ switch, yes it would improve your transmit time.

For your Internet connection, I agree with JFrederick - it will be limited by the speed of your DSL connection, so it doesn't make a lot of sense to worry about it.  I would note that there is a small exception - if you can run at 100 Full Duplex (or hopefully autonegotiate/autonegotiate on both ends) then this will eliminate collisions and errors caused by duplex mismatching in the connection between the DSL modem and your network equipment.