This has been a hot topic lately. Many many thanks to Alan H. (SVT_Alan) and Jojomofo21 for helping me with the info on this install. Alan posted a how to up on Facebook and he sent it to me since I am not on groups. This whole thing can be done for well under $500 and depending on what options for under $400. Great upgrade over the stock Floating 2 Pistons. The ATS is 4 Piston and just look much better in my opinion. I am posting parts I did and hopefully help others. **RockAuto 5% coupon code expires 7/28/19: 110511239104454439 **** Parts needed: 2013-2018 Cadillac ATS Brembo Brake Calipers PN: 172-2777 and 172-2768. ($121.79/each) 2. 4 Flanged 10.9 M14x2.0x40mm Bolts. ($7.59 for 5) 3. Brake Pads for the J55 brake kit for 2013-2018 Caddy ATS. I installed Power Stop Z23-1001. ($40.99) 4. A HSS 9/16 or 14mm drill bit. (had one) **EDIT** S&S Engineering Spindle Kit. Contact: [email protected] Photo's of kit in Post #2. 5. A rat's tail file (had one) Optional Parts 6. New Cobra rotors if you want to replace yours while out. I installed AR8144/8145XPR. ($89.98/pr) 7. Also Optional is the Stop-Tech 950-61001 comes with correct Banjo bolts. SS lines are one of the best improvements you can do to your brake system so I highly recommend it. ($55.43) 8. Brake Fluid for bleeding the brakes (~$9) 9. Caliper paint (~$8) The parts can be purchased at many places. The calipers can be purchased at Rockauto.com, Amazon.com, SummitRacing.com along with many others. Depending on your state tax laws and shipping prices as to who has the best price. The bolts and drill bit can be bought from McMaster-Carr. Brake pads and rotors can be bought anywhere but when I bought them the best price was Rockauto for the Powerstop Rotors. Best price we found on the Stop-Tech SS lines was PartsGeek.com. Also you can always find a coupon for 5% off at rock auto. Not a lot but it is something. The biggest part of this mod is machining .075" off the back of the Brembo mounting tabs where they bolt to the spindle. This is very important as it helps center the rotor. They need to be flush so don't use a grinder. This is also a good time to paint or powder coat your calipers and put on a logo if you want. Cadillac is printed on there so it can easily be skuffed up and painted over. Next we get to the car. Put the car on a lift or jack-stands and remove the wheels, brake calipers, rotors, and brake lines if you are replacing those. Once everything is removed you need to take the drill bit and is drill out the two holes on the spindle. The new bolts will just barely slide in. Next you want to take the rat's tail file and file the two holes towards each other. You want to file a little bit and then put the calipers up and see if you can screw the bolts in by hand. If not file a little bit more off. The Brake pads are a little too tall. You will have to grind 6mm off the top so they sit even with the rotor. We marked 6mm from top of pad all the way across the top and then used an air grinder to make quick work of it. It is VERY messy and don't breath the brake dust. I think Alan used a Belt grinder and his came out way better than mine. So that is another option. Once you get the Caliper to mount all the way remove them. Now is time to put the rotors on and bolt the caliper back on. With the Brembos calipers full bolted down you drop the pads down the back and slide a pin in to hold the pads in place and then put the metal clip in and slide the other pin in through the pad holders and push the other side of the clip down. At any point you can install the new brake lines. They make a bit of a mess so make sure you have a drip pan to catch the mess. Once all the parts are back in place mount the wheels and bleed the brake system. Enjoy and Good Luck! I will continue to edit and update this hoping to help others.