HP gains

[series 7]

Im looking for more power out of my boxster and I was wondering what route I should take. I dont know how much power I could get from intake/exhaust/headers/ecu, but I was looking there. My first choice is that if the power is enough, but I'm thinking very heavily on taking her under the knife and throwing a 996 engine in. Im looking for power to be around or over 270/280 and I dont think that normal mods are going to cut it. I would supercharge it, but I dont know how safe/reliable they are. I already have access to the engine/tranny from a 911. Can anyone tell me the experiences they have had with mods and power gains? Anyone have a supercharger? I would be very interested in one if it's reliable enough.