What is the proper way to build RELENG_5 w/o IPv6 && w/IPSEC ?

Dear FreeBSD team people,

While following the thread about IPSEC issues, I'we got somewhat confused,
maybe someone will be so kind to spend a minute and tell me the answer:

I'm preparing a RELENG_5 (5.3-STABLE) system to act as a network server.

IPv4 and IPSEC are the must. VLANs, various tunneling and VPN features also
are the must. Zebra w/BGP4 will do routing. And IPv6 is of no use here.

What is the recommended way to set up make.conf and kernel config variables
in order to get world and kernel *both* automagically satisfy the above
requirements, get decent network performance, and at the same time - to
avoid building unnessecary IPv6 bells & whistles? (and at the same time - do
not break some potentially useful stuff).

The machine is P-IV 3.0 w/HTT, Intel S875WP1 motherboard (em0 && fxp0
interfaces).

Thank you for your suggestions,
Andrew