Is This Possible??? Horsepower Question...

[Magik Si]

I'm driving a 90 Civic HB Si but when I got it it was supposed to be a "parts" car for my other Civic that met up with a Dodge Ram shortly thereafter.
It had in it a dying D15B2 that someone has swaped into it instead of the stock engine...I believe it was the head gasket...it was spitting oil all over the engine bay and burning it like crazy.
So I had a spare engine from my first Civic (STD) that worked great, so I threw that in there....it's a D15B1.

I've kept in the original MPFI and the 5sp tranny out of the Si and matched it up with the D15B1...but how can I squeeze more out of it? I know that the engine when it was in the STD had only about 70hp...and I imagine that has improved with the addition of the mpfi of the Si (even thought it's a little heavier car)...but how can I squeeze more out of it?

Is it possible to get 100hp out of this engine? 120...150??? If so...how can I do it? Dumb this down guys, I'm still learning, and thanks for any help.

Jason

(Wierd I had to post this twice to get it to take...)