well i went for it ...... upgrading via the stock firmware GUI directly to one of the newest TomatoUSB - Toastman builds for this router..... a VLAN version for me.
30/30/30 reset before flashing the *.bin file and after the upgrade is complete.
you must change your ethernet port to Manual IP, sub and gateway
NOT DHCP as DHCP is not enabled by default with this firmware.
You CAN NOT use wireless to flash, you must use ethernet.
thats about it, make and leave the thing alone for awhile after flashing it and then doing your final 30/30/30 reset...... and of course enable DHCP for the IP Range your on.... wireless security etc.
maybe this will help someone in the future.
some info on the web for the various builds and DD-WRT wiki page for your model router.