More Hp!!

[4.4i]

Ok, heres the story. I have a 2004 BMW X5, im looking for a way to boost the hosre power of this car. So for i've put new piston heads on the car, cleaned the filters and got an ECU chip installed. Is there anyway i can get an Intercooler installed? If anyone has any Tips on what more i can do for more Hp that would help alot. Thanks

PS. Im trying to avoid paying an arm and and a leg for someone like Hamann to do this.

[Antiburn]

Put a dinan supercharger on it. If you can find a cam for it, you can also get an intake on it. Get a larger throttel body and if anyone makes it try to find an exhaust.