USR2450 implimentation

[I was beginning to doubt the viability of my USR2450s, it seems you 
guys are still interested in advancing with them...]

I am doing WDS and WEP on a 4 node (all USR2450) system.  The 
performance is pretty bad.  I know that both of these kill 
performance...  Can someone tell me from experience what to expect from 
WEP vs non-WEP?  Speeds?  Also, what are some alternatives to WEP?  
IPSec?  But can the 2450 do that?

I'm thinking that maybe I will have the users VPN into a server that is 
accessible through the "public" non-WEP wireless mesh-thing.  But it 
would be better if I didn't have to throw a full sized computer at the 
problem.  Also, the public wireless network could be abused or DOSed.

Right now I have WDS on each of the 4 APs bridging to the other 3 APs.  
I might have some weird cascading going on.  But I thought WDS was 
supposed to find shortest routes for you?

Any advice?

Thanks,
-Scott

PS- I have recently purchased a WRT54G to add to the mix or run beside.  
Maybe that can have enough RAM and CPU to do IPSec for the others?