I was referred to this place by another member. Still havent gotten it done yet, but I was told that they have done it and did a really good job.
From the other member:
Best Muffler. It's located in La Crescenta/Glendale area, the guy has experience with this so that's definitely a plus. Here's the address:
3947 Foothill Blvd.
La Crescenta, CA 91214
2012 Jerez Black E92 ZCP - MS Stage II - Custom Molded Challenge GT CF Race Diffuser - Custom Molded Gintani CF Rear Side Skirts - Custom Molded BMW Performance Splitters - Custom Molded BMW Performance Rear Spolier - RKP CRT CF Front Spoiler - Megan Racing Exhaust - Satin Black ZCPs - MS 15/12 MM - AiB 4.0 - KW V3 - BC Forged TM-14 - BBS LM