I have FD1 Honda Civic (1.8L SOHC iVTEC), what's the best upgrade to do to gain power? Have the cam ground? Already has a Mugen Exhaust?

I have FD1 Honda Civic (1.8L SOHC iVTEC), what's the best upgrade to do to gain power? Have the cam ground? Already has a Mugen Exhaust?

Put a V8 on it.

Sell it and buy a Type R. Any mods that will give a significant performance boost would make an acceptable down payment on one.