The installation is a piece of cake! Pop off the trim pieces (keeping them so I can remove and sell the rails come trade-in time), put the spacers in place with the arrows pointing forward. Place the side rails on the roof ensuring the rubber is still properly attached and over the channel. Line up the bolt holes and insert the bolts. Torque the bolts to the proper setting, insert the plastic covers and done. Absolutely silent and they look great. My black GT model came with the chrome trim on the doors so the roof rails compliment them nicely.
BTW, I had tried to save some money and bought a fixed-point roof rack for my CX-3 last winter to hold my ski rack and they whistled so loudly I had to remove them after each use. Since that was such a PIA, I sold them and decided to go with the OEM rack. I found a set of cross bars online that a former owner had removed from their car before trade-in and got a good deal on those for $80CDN. I searched for a used set of side rails for a couple of months and had no luck. I was unsure of the quality of the aftermarket side rails found on eBay, and since they were only $50 less than the OEM part through Mazda, I decided to get them at my local dealer.