You should not disable CEF on the Layer-3-Switch since this will disable hardware-based Layer3-Routing.
To process-switch traffic, the CPU in the 3550 is much too small.
Also, a Cat 3550 does not have sufficient memory to keep a bgp full-table, or two of them.
I would suggest to use at least one or a pair of 2821 router with 1GByte of Ram to do so,
(of course better a pair of 7201 with 2GByte of RAM).
Today, CEF ist working fine in most IOS Versions and many Cisco-uniqe features rely on it.
You may disable soft-config do save memory in BGP.
But iff you have just one upstream, you do not need BGP-full tables but only default-route,
and inject your own prefix. (You do not need bgp or an AS for that with just one connection).
just my 0.01 $,