I bought these as an upgrade for my de motor. These will bolt up to a de motor but you have to move the middle two studs to the other side of the exhaust port on the head. If you’re considering this as an upgrade to your de motor then make sure you have cats/test pipes that are for an hr as well. Catbacks are not de or hr specific so don’t worry about that. These are good headers, very strong, flow well, and smoothen the exhaust note because they’re a lot closer to equal length than the oem de headers. If you’re attempting to do this install yourself, good luck. This install took me and my friend multiple days. Were not mechanics but we’re also not beginners for working on cars. If you’re comfortable pulling the motor, do it. For those of you who don’t want to pull the motor here’s the basic steps for a de header swap. Drain the coolant, remove the intake, remove the vacuum lines that are in the way, remove the metal coolant lines on both sides of the motor (some of these bolts are very hidden), go underneath the car and remove the cats or whatever you put in their place. You have to access some of the header to cat bolts from the top of the motor with an absurd amount of extensions. Disconnect the steering column from the steering rack at the u joint (remember exactly how this went together or your steering wheel will be misaligned), unbolt the bolts that hold the headers to the head, slide the headers out from under the car. Next swap the studs around the center exhaust port, transfer the oxygen sensors and studs that were on the old headers to the new hr ones. Should be one stud and sensor per header. Next put in the new hr headers (don’t forget the gaskets) and your new hr cats/test pipes and then put everything back together, add coolant and bleed the cooling system. I didn’t torque any of the bolts because it’s basically impossible to fit a torque wrench on any of these bolts. Godspeed to anyone who attempts this.