I don't think the Felt Footprint is very light...
website says 18.7 pounds.
is your langster steel or aluminum?
if it's aluminum i think you'd get a better value just upgrading with lighter components
and are you riding it SS now? if so, what's the problem?
i know people that ride without rear brakes SS.
or just ride it fixed.
or get someone to drill a rear brake.
bottom line: i wouldn't consider that much of an upgrade at all, just an extravagance.