Ok so I have determined the issue with mine. Apparently with the newest DME software available at dealership has an issue with catless downpipes even with JB4 turned on. The DME's can see cat efficiency immediately even with JB4 clearing fault memory on every start-up, so the fault would come back in less than a minute. Installed factory cats back on vehicle, problem solved immediately. I then drove it for 2 weeks, never once did the idle fluctuate or engine stall during cold start. I miss the sound and throttle response with the catless and I've found a solution for less than $100. All you need is 2 of these,
http://www.ebay.com/itm/Catted-O2-ox...ZYR88f&vxp=mtr They fit just using the straight part. Not so sure what the deal is with the stock catted cars though. But mine is fixed!!