No problem!
The next challenge aside from finding an OEM downpipe is performing a drive cycle. Had to this once on an E60 M5, its the reason why I hesitate going catless again.
Remediation steps:
1. Install OEM DP
2. Load Stage I tune or stock tune. This will generate a bunch of error codes that will need to be cleared.
3. Let the car sit over night. Prepare for a Drive Cycle
4. I bought this device connected while driving so I can monitor in real time
Step 1: Start engine, connect scanner to OBD port, press I/M button which shows CAT, O2S & AIR in red. HCAT & EGR grayed out. The rest are green.
After 3 minutes of idle, Air goes green.
Step 2: Challenging @ 25MPH for 4 minutes without going below or above the speed guideline. Avoid streets w/stop signs & stop lights. Best to do this late at night in some areas. Pull over, turned the engine off, then on & begin the drive. Slightly before the 4 minutes is up, O2S goes green
Step 3: Pull over on the side of the fwy, turned off engine, then on & begin the drive. A little over 7 minutes the CAT goes green.
Last challenge hopefully you don't have this problem is the visual inspection. If you have aftermarket cold air intakes outside of Dinan or maybe AFE, chances are they will fail you. The will ask\look for a California Air Resources Board (CARB) sticker.
Good luck dude!!