An easy solution is in cali for the exhaust. I flew in to Socal from Houston before heading north (home) and i must say "very impressive" he explained the entire 8 months of RnD on his system and his final version was best sounding i've heard for non turbo.. NO dronning (sport or non sport modes in) any given time, the power n torgue his 328i produced was by far the biggest surprise. Im confident he has a tune he refuse to let out of the bag bc my buddy has similar tune and mods but does not produce the same power.
Sound: When driven standard its fairly quiet but, sport gears or manual high RPM, sound was music to my ears. All i can remember is the amount of attention his car was getting. Looked around stop light and i remember seeing faces driving behind him " Holy Shit Look". I was sold and ordered mine and takes a two weeks as he custom make per order.
I was breezing thru here to sell some M5 wheels and ran into this post. Since they refuse to allow him to become a vendor and as a customer of his (modded my entire front end from SoCal and organized all front end work needed for lci conversion local body shop). His work deserves to be passed on to others as he offers full custom mods. I advised him about this request and he asked me to extend his offering of a sponsorship or group price if anyone is local in socal or he can also ship. According to him, we have similar engines as the 530 or 528?
His system is very affordable for what he offers. its a True Dual System 2nd cat delete replaced with X pipe with 2 race rasonators and race mufflers. He had quads but went back to dual for some odd reason but i ordered quads for my car (no need to remove storage bin).. I only have pics i took form my camera but here's a link of a video. He also stated "He increased the piping quarter inch so its a tad louder and will have a new video soon" .
I bought mine for 1675 full catback and sponsorship price im assuming will be discounted compared to what i paid..
links.. you will see several different ones during his RnD phase. I believe he went thru 5 different set ups before his final one which finished last week.