I'm lookin for someone who knows from experenice. I have heard from many sources that an i head on an e block is not what everyone makes it out to be. It make output worse. I have already had the head planed 30thous and it bumped compression to 9.5:1. You can't reach that with an i block. In fact the only head that will add power to an e block is a head off an E36 2.0 motor. That will raise up to 30 hp. This i know for a fact. It's just not cheap.
As for exhuast i have that done already. I totally rebuild the motor, doin little things to it that freed up power.
the dyno read 138 hp
with 185ft/lbs of torque
that was with a faulty o2 senser
i have also heard from many sources (including BMW) that cool air intake is one of the best things you can do to the motor. when These cars came off the line BMW purposely restricted airflow and exhaust to make the motor quieter.
what have you guys done to your cars to improve performance? I know what can be done. I am more curious to see what is worth doing