M Performance Exhaust Installed on '13 640i GC

I didn't want to hijack another thread, so started a new one!

I had the M Performance Exhaust installed on my 2013 640i Gran Coupe. I'll give a brief synopsis of the install and results, and of course will answer questions as Best I can. I was not able to get great before or after clips, but nonetheless have a couple for you to hear, and plenty of pictures of the belly of the car and exhaust. There may be what looks like repetative pictures, but I tried to get different lighting to highlight what was important. Forgive me if there are too many.

The install was done by one of the BMW Centers best mechanics. He had also installed same on an F30 and 535i. Total time actually took about 2 hours, 45 minutes as we spent a bit of time fine tuning the position of the exhaust (more below).

He referred to the instructions on his system (none included in box) just to be sure, although was somewhat self explanatory. He found the referenced cutting marks on original exhaust pipe, and cut his way through the left muffler first. Not as quick as we would have liked, as the top wasn't easy to get the cutter's pressure on, vs. the rest of the pipe. Once cut, he unbolted the existing muffler hangers, supported the muffler, and removed it. The existing tips are welded on. My kit came with screw on tips (which I prefer anyway). We took a little time figuring out which way the clamp should be mounted, bolt wise, and mounted the hangers to the new muffler and hung it. The 2 metal pipes do NOT align exactly as they should, and in fact, aren't even really close for centering the tail pipe in it's place. Upon tightening the Clamp, the muffler moves out of center, and a bit of creativity and patience was needed.

Same was done for the right side, and of course quite a bit quicker. Once we got the mufflers to a point were both tips were equally spaced within its cutout, everything was rechecked as to torque, and placement. Tips were put on tight enough to drop car and check placement. A little here, a little there, and we got them where I like them best. Not too far out, but the M is noticeable if youre looking for it. If your not, you won't notice them anyway, for the average non-BMW enthusiast.

In the end, install wise, the tips are not perfectly centered within the holes. the have a slight tilt toward center of rear bumper and are edged closer to the inside of the cutouts than the outside. The tech and I could have spent more time attempting to bend the hanger rods to the exhausts or use some straps to shift the back just a tad, but we also know that the more we put tension on it, the more issues I'll have day to day, such as rattles, noises, etc. I'm happy with the placement and it no doubt fits as designed.

So, with the tail pipes firmly tightened, it was time for a sound check. WOW! I hadn't the foggiest idea what to expect, other than to trust my friends in Munich (or California Design) that they wouldn't disappoint, and they did not. It has an awesome, deep sound that is not obnoxious, is well liked and sounds awesome. In fact, a prior model M6 coupe was across the bay, getting revved up by it's mechanic. My little 640i sounded leaps and bounds better, and that's from all mechanics in the shop!

On the drive out, with building and car lot echoes, it sounded sweet. Hit the highway, and you absolutely know your exhaust was upgraded. Sounds amazing. At 70MPH, all windows up, with the drop of a gear or two, you hear it well inside the car. No drone! But you do hear it. Again, you know it's there. At normal drives, letting the car run in full auto, you get a nice, sweet sound for a few milliseconds, then again on gear changes, a few snap crackles and pops, and othewise, it's just great. Not intrusive, but much appreciated!


Enjoy the pics and video clips.

and a couple more shots and the audio clips.

Car sounds amazing with the M performance exhaust!

Good sound. Your BOV is so audible! Me likey . Anything else done besides exhaust, that could contribute to the BOV being louder?

Sounds great.
Don't know why they don't make these stock.

Originally Posted by BigDeep1

Good sound. Your BOV is so audible! Me likey . Anything else done besides exhaust, that could contribute to the BOV being louder?

No other add ons. I will say after a week with the exhaust, while it sounds great, it does carry somewhat inside the cabin. Maybe a little too much. It is less noticeable in SPORT mode. Dealer is going to check it out again Monday.

Best way to describe is that it kind of lingers with a bass that is quite noticeable until about 7th gear, all speeds. Again though, it a great sound, not disturbing but it does make me wonder a little. It not a reverb or bad drone, but if I had to use the word drone, I'd say its minor at best.

I love the little crackles that it makes at almost all gear changes at times. It isn't very often, but just right!

I put the M exhaust on my 535i 2011 and you described it perfectly. I had Magnaflow on before. Way way more drone.

Which has more drone? The magma flow or m?

Huh. Never new how it was done. I just dropped the car off and picked it up at the EOD. Mine seem pretty centered. Didn't do any exact measuring but they looked fine to me. Congratulations!!