so after talking to a retailer who sells hawk pads ive learned the HF pads are 4" wide by 1 3/4 tall, and the SI brakes are 5" long by 2" tall. according to the buybrakes.com website brembo has listed the 88-89 SI/DX as the same rotor, but the 90-91 DX/SI as different part numbers. HF the same from 88-91 HF rotors show as: Type: Ventilated Disc Overall Diameter: 231mm Minimum Thickness: 15mm Overall Height: 43.8mmFits: 1984 - 1987 HONDA CIVIC HATCHBACK w/ Vented Front Disc 1983 HONDA CIVIC SEDAN 1984 - 1987 HONDA CIVIC SEDAN 1984 - 1987 HONDA CIVIC WAGON / WAGOVAN 4WD 1984 HONDA CRX 1500 DX 1985 - 1987 HONDA CRX DX / SI 1988 - 1989 HONDA CRX HF 1990 - 1991 HONDA CRX HF 2000 - 2002 HONDA INSIGHT The SI brake rotors show as: Type: Ventilated Disc Overall Diameter: 242mm Minimum Thickness: 17mm Overall Height: 44mmFits: 1986 - 1989 ACURA INTEGRA 1988 - 1989 HONDA CIVIC HATCHBACK 1988 - 1989 HONDA CIVIC SEDAN 1988 - 1989 HONDA CIVIC WAGON / WAGOVAN 1990 - 1991 HONDA CIVIC WAGON / WAGOVAN 4WD 1988 - 1989 HONDA CRX DX / SI 1990 - 1991 HONDA CRX SI This is a really hefty difference for me in friction swept surface area as well as just plain overall rotor diameter. I was wondering if anyone has tried swapping HF brakes to SI brakes? I dont want some ungodly huge poorly biased crappy brake setup. What is needed exactly? Will it still clear 13" hf wheels? Do I need the SI caliper bracket or can I use the HF one? This is currently one of the bigger obstacle questions as it doesnt seem I can get my hands on the brackets anywhere. EDIT: according to hondaautomotiveparts.com, the HF and the SI/DX have the same part # when searching for the knuckle. Great, that means anything that bolts to the SI bolts to the HF. I will edit the thread and post my results as I go, any input from others is appreciated. im assuming crx's all have 56.1mm center bore ok so I guess it doesnt matter much if the brackets line up, I just found them at a local junk. They are gonna pull the calipers and brackets then give em to me for 60 bucks shipped. I will install them, and probabbly measure between the 2 and post up whether or not the brackets are the same.