What plugs do you have and what are the gaps? The ignition system on these cars are terrible and it needs to be 100% fit, you are running alot more boost than you were before and the ignition systems needs to be man enough for it.

The CO is critical and checking comes hand in hand with the new setup.

You shoulden't have to change the fuel pressure unless the new software requires it to be changed, pretty sure all chips of this spec are written for standard, but check the instructions to confirm.

What makes you think you experienced overboost protection and you just wern't misfiring up the road?

Martin