I've had the Mountune CBE on for a few days and about 100 miles now so I thought I'd post a proper review.
PRICE
As I mentioned these can be found for 15-20% off retail price. Being 3 years in these are old news and I am sure Mountune would like to rid their shelves of them, especially now that there are other cheaper CBEs on the market.
QUALITY
Great fit, great quality of course, you get what you pay for here, no banging under the car or anything, there is only one way to install this - I read somewhere that there was adjustment - there is not. You could theoretically leave the 3 sections spaced a bit apart but it would not affect the outcome of how far the muffler tips stick out because that is dependent on the hangers, not the pipe. I know because I tried to push them out a bit further by not seating the pipes completely (we're talking one inch) but it did not make a difference, the pipe is going to sit where it wants.
INSTALL
Install was about 75 minutes on a lift, I was gonna do it on ramps but screw that, who wants to get under the car with a sawzall on ramps or jack stands? Not me. Anyhow a few tips:
(1) Make the cut in a straight piece, that way if you ever go back to stock and sell the CBE you can easily get a splicer, put the stocker on, and make a few hundred clams off the sale. If you cut on a bend it's much harder to do this.
(2) Be careful not to cut into your gas tank, it's right there where you're working.
(3) Surely enough one of my DP bolts was bad, it took some massaging to get it off and once I did it was pretty stripped. FORD! Erggg. But with care and precision I got the nut back on without crossthreading. Use plenty of PB plaster for removal and use some grease for re-install and it shouldn't be a problem.
(4) I and others found that once tightened the muffler tips do touch the bumper cover. To remedy this you can get a longer exhaust hanger or fabricate some other method. As of this writing I've got a hose clamp holding it all together but I have a hanger on the way which will be a permanent fix.
LOOK
One issue, already addressed in the install notes above, if you want it spaced correctly with the tips visible you'll need to get a slightly longer exhaust hanger....at least I did. Aside from that, the one part of the exhaust you see (tips) look awesome and are slightly larger than OEM but not much, they look super and the M is nice to see as I approach the car. I painted the back of the silver can black for stealth, it looks great and matches my car.
VOLUME
So here is where I actually think it could be a bit louder. I wanted a quiet exhaust and it is, but maybe a bit too quiet. Prior to this I had my resonator removed which maybe added 5% sound. Now with the Mountune we're at about a 15% increase. On start-up there is a very slight difference, most people will not notice unless they're into cars. Accelerate and there is more sound. Around 2,000 rpms whether accelerating or cruising there is a but of sound, call it drone or sound, either way it's not bad at all and is quite nice. Bottom line is that this is an exhaust for grown-ups, a stealth exhaust. It's there but not that much. For me coming from the exhaust resonator delete it made it even more subtle. Had I not removed the resonator a few months ago and gone straight to the CBE I might be more affected. Also of note as others have said you might plug your symposer when adding the CBE, I did because the two sounds conflict and it's annoying.
TONE
Here is where this exhaust shines again, the tone is outstanding. I daresay it sounds a bit like a boxer engine now, reminds me a bit of my Subaru at idle. It just sounds so deep and rumbly and high quality. Rev the engine, as the rpms decrease there is a beautiful rumble and gargle. Not ricey at all - as others have said it just sounds so good. It sounds like an OEM quality exhaust but one that is tuned to be sporty. It sounds just like what Ford wanted when they partnered with Mountune to get a warranty-friendly part that still sounded "like Ford performance" if that makes sense. If it were a bit louder it would be cool since the sound is so great.
PERFORMANCE
Probably nothing to speak of here, though I keep an close eye on both my estimated torque and MPGs, and in the 100 miles I've driven both have increased ever so slightly. I'm 3/4 tank full of gas and already logged 150 miles which is unusual. The exhaust is 2.5" as opposed to the 2.25" OEM IIRC so there is some more flow there, if not just a bit. Estimated torque is a few points up too. But it's nothing you can feel, and if you do it's placebo. When it's not hell hot outside I'll take a few datalogs and my tuner Mr. Brunson offered to take a look free of charge and see if there are any tuning adjustments to be made. When that happens I'll report back.
***************
Overall this is a great CBE and I highly recommend it. Could be a bit louder, and the muffler touching the bumper is a small issue, but it's about perfect for my needs and definitely the best choice for what I wanted so I am extremely happy and recommend this to anyone looking for a high quality great sounding non droning exhaust.