What can you add to an BMW M3?

[StilliRis3]

I have a 2004 BMW e46 M3 coupe.

I added a lot of stuff to the interior and the body so it looks great.

But now only thing I have left to do is to add stuff to the engine.

I am thinking about definitely adding new exhaust, intake, blow off, powerchip and other minor stuff.

But for the major part, I want to add like stage turbo, twin turbo, or a supercharger.

I know this would cost alot but which one would be the best thing to do?

I am looking for great performance with the car.

Also, is there anything that you can do to make the car handling even better?

Thanks.