I just recently installed the SPELAB 2.5 inch Remote Dual Electric Vacuum Valve Electric Exhaust Cutout Kit on my 2013 535i xdrive and I love it! I have attached pictures of my setup in this post. First of all, SPELAB's customer service was great; they are fast to respond and will ensure everything is correct with your order. One of the cutout valves would not open all the way and SPELAB sent an entirely new set of cutouts, no questions asked. They did not even require me to send back the old cutouts. As far as the product, it is high quality and works as intended. I had my local exhaust shop weld them in right before my mufflers. The wiring was easy and I was able to snake the vacuum lines through a little grommet that leads to the trunk. From there, I zip-tied the vacuum box to the frame of the car next to the fuse box. You can use the cigarette lighter plug that it comes with, or you can cut it off and put it directly to a switch in the fuse box like I did. I even paired the remote for the valves to the garage door opener on my rearview mirror for easy use. When opened, the car is much louder. When closed, the car sounds completely stock. I will use these on every car I own from now on.
Here is a link to buy if interested:
https://www.spelabautoparts.com/coll...ust-cutout-kit
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