[c-nsp] 3845 + BGP + FW/NAT vs. 6503+Sup32 ?

[matthew zeier]

I know this is a seemingly ridiculous comparison but the pricing on a 3845 
with extra memory came in only slightly cheaper than a 6503+Sup32.

I posted earlier about the 3800 as a dual feed BGP router and got mixed feedback.

The basic network will have two ISPs coming across ethernet (by way of a 
DS3-ethernet bridge - Overture ISG 45).  The router will peer with both 
providers and take full routes.

Inside I'll have four or more networks in RFC1918 space NAT'd out and use 
IOS-FW to policy traffic between networks.  Since the 3845 only comes with two 
onboard NICs, I'll use sub-interfaces - the Sup32 has 9 and I'll probably just 
use one per network.

Today, inter-vlan traffic is < 10Mbps and aggregate outbound traffic is 
~6Mbps.  How long can I expect the 3845 to live?  How much traffic can I 
expect it to push inter-vlan?  Would I be "better" off spending the $5k or so 
more and getting the 6503+Sup32?

I'm concerned about getting a box that will suffer under traffic loads and 
ACL/FW/NAT rules.  Any help would be great!