c'on, 5 minutes no way.
i happily need to be there only every 2 years to pay the tax for my residncy renewal, always in november, last time 2006 nov.
it takes at least 20-40 minutes in the line for the cashier where you pay the tax, and anything which has to be paid will be paid at those cashiers in the front lobby of the migration. after that it takes an other 20-40 minutes til the renewed card cames out, ready to go.
maybe there's an other migration office which i don't know, i am always at their main building where you have to do all that residency stuff.
if there's an other place please post it, it's always helpful to know a shortcut on that stuff, i hate those day long travels anyways from PC to the capital to do some paper work aso, always full traffic on the streets, nothing to like about.
have fun
Mike