Whoops, let me be more specific.

It would be a good idea to put the stock pulley back on until you can get more mods, lest you risk the integrity of your engine.

To run a 3.0 pulley, you will need exhaust like you said, headers, bigger downpipe with a u-bend delete, colder spark plugs, a 180 thermostat, a custom tune, etc, plus .. a 3.0" pulley is territory that is hard to define as it differs from car to car, but it's safe to assume that you will need rockers or a cam, and an intercooler, or you'll most likely find yourself busting engine internals from the increased boost.

If you're relying on this car as a daily driver, I really suggest not going as far as a 3.0 pulley, as you'll really be comprimising the reliability of your car. Unless you have the ability to keep throwing money at it, then by all means. At least have an alternate mode of transportation to keep yourself in stride with the downtime your car will probably have. If you're hellbent on a 3.0, though, you might want to check into getting a built tranny as well, because that will probably be the first thing to go.