I have added a few HP to my sephia. It has the 1.8L 16V DOHC.
I put a header, 2.25" cat-back with high flow cat- around 12-18HP
I boughta lightened crank pulley-about 5 HP
Cold air intake-1-2HP
can get all of this stuff at www.kfxperformance.com
hope this helps you out a little!