Dammm... that's phucked up.
To answer your question, it all depends on three things:
1. Time
2. Money
3. Power Goals
If you have alot of the first two and you want as much power as possible, the you can afford to build the bottomend with high compression forged pistons. Also, if money and time aren't a factor, I would also suggest the Port & Polish with the 3-5 angle valve job. Get the head shaved, and slap a full valvetrain rehaul in that bad boy! Full top-of-the-line bolt ons from there...

... That's in an idealistic world that few of us get to live in. Since you said, it's already in the car, all of this would only be able to be achieved if you baught a whole other motor build while you still drove the other one. Get a good header, intake, and a mild cam, and tune it. Spray... 50 shot.
The tourque of the B20 mathced with the added power from the upgraded flow will equal a nice moderate streetable setup. But, for more power, more money and time will be required.
