did you pull your ecu codes?
sounds like knock sensor is retarding your shit to me.
open downpipe, idle rough, black smoke, misfiring until 4500 rpm then backfire.
Lets take it for a spin 2009-05-15 on Vimeo
pulled ecu codes.
Simone Video Blog - Throwing Codes on Vimeo
ecu diagnostic of the maf sensor.
Simone Video Blog - Performing an ECU Diagnostic on Vimeo
jumping the knock sensor to eleminate the possibility it's making the car run like this.
Simone Video Blog : Knock Sensor Magic on Vimeo
what do you know... knock sensor went bad somehow. that ticking noise you hear when it's decelerating was the flywheel, old bolts stretched and backed out and has since been fixed.