I've got a 2003 GTP which is bone stock at the moment. The goal is to surprise a few mustangs and hit 13's. Nothing too crazy, as this is my daily driver. I've been searching through the forums and yes I've read the "safely modding your 3800" thread. I've been looking at picking up a set of headers as it seems that's the most common place to start after an intake. I've read with SSAC headers you have to clamp a high flow cat in if you want to use one. This results in a P0420 code evidently? It sounds like any basic tuner can shut the code off for me, but I get the impression that some companies are preferred over others. Which brings me to my next question... Who's the best place to get a PCM from? It sounds like I should do both of these at the same time, before even looking at anything else. Any suggestions guys? I've spent most of my time working on carbureted v8's, so this is a different world for me.