After extensive research, I finally took the dive and upgraded my 2015 Mirage with 2017 brake caliper brackets and disc and pads to an even bigger OEM upgrade.
Note: I understand this upgrade is a bit more involved and some of you may not agree with what I have done and have concerns for safety, etc. So this is for entertainment purposes only, but I have had this setup for over 1,000 miles and think it works. Do at your own risk.
Stock OEM 2017 brake specs:
Disc size is 251mm wide x 42mm height x 17mm thick
with 4x100 bolt pattern
brake pad size is 122.11mm x 43.9 x 14.4
brake caliper piston is 51mm
Upgraded parts list:
All parts can be sourced from a 2001 Mitsubishi Mirage (make sure it is the 14'' wheel version (1.8 Liter) if you look at older models of the same generation, such as 99, 00)
Disc size is 256mm Wide x 45mm Height x 24.5mm thick
Brake pad size is 128mm x 52mm x 15.7mm
brake caliper piston is 54mm
Front left and front right 2001 Mirage brake calipers (and brake pad shims and clips and hardware)
2 front 2001 Mirage Brake Disc/rotors
1 set of 2001 Mirage Brake pads
Grinder or access to a milling machine or 2.5 or 3mm wheel spacer or 2.5mm 12mm washers
new brake hose washers (if you feel like you need them, I reused my oem ones from the stock caliper and it was fine and you will need to bleed your brakes)
I bought reconditioned calipers and new brake disc and pads online and I believe came out to be about 250 dollars for everything. You can definitely do this much cheaper by going to local junkyard or pick n pull.
That's it Everything bolts on and you can reuse your oem caliper bracket bolts and oem brake line bolts. you may watch a guide on how to change 2001 mirage brake pads on youtube if you want to figure out how to install this. Except the drawback/modification below:
two ways to attack this. Either shave 2.5 to 3mm off the brake cailper mounting bracket of the 2001 mirage brake caliper, you would shave the side that touches between the wheel hub and the brake mounting bracket, not the bolt head side.
This is because the brake disc/rotor will scrap along the inside of the caliper mount bracket and you need the additional 2.5 to 3mm to recenter the brake disc/rotor. This is nothing new as the Honda and Acura community shaves/grinds/mills integra brake caliper brackets to fit civics and etc.
2nd option is the install a 2.5 or 3mm wheel spacer shim under the brake disc which effectively moves the brake disc more centered between the brake caliper. (I've done this using a 3mm 4x100 wheel spacer (20 bucks on ebay) from a honda 56.1mm and bored it out to the brake rotor disc size of 64.1mm with a metal burr) and I've done this using four 12mm washers that were 2.5mm thick stainless steel from Lowes for 4 bucks. Choice is yours. I didn't notice any noticeable difference in steering wheel shake on highway with the spacers or washers.
with the 3mm wheel spacer, i felt like I did not need to use extended lug nuts and have enough threads on to tighten the wheel. Although, after a few miles, i did check and re-torque my wheels to make sure they were on tight.
The advantage i see here was a much thicker brake rotor which will have better heat properties and a bigger brake pad and a bigger brake piston although the overall width of the disc is similar. Although you can argue more rotational mass, etc. Again, you can choose to this modification if you like.
The good news with the 2001 Mirage disc size being similar is that it fits under the 14'' Alloy wheels I had, although you will need a spacer, i only had a 25mm spacer on hand and it fit with the 25mm spacer. but I am not sure about the 14'' oem steelies as I do not have any available. For reference, I am currently using 15'' alloys from an Acura integra known as the fat fives and have plenty of brake caliper clearance with no spacers except the 3mm wheel space noted below to center the brake rotor.
With the 54mm versus 51mm brake caliper piston, some say you need a bigger master cylinder to avoid having a squishy brake pedal. I didn't notice a huge difference on the brake pedal feel as the brake power of the bigger 2001 mirage brakes seem to stop a lot better. Nor did i find an appropriate master cylinder that would fit (please let me know if anyone finds one, our 2014 OEM one is 3/4 inch only and upgrading to a 15/16'' or so may provide better brake pedal feel)
Again, I understand this is not for everyone but i wanted to put this information out to the forum and community.
A bit more information is that the 1992 Mitsubish galant should use the same 128mm mount center for the brake caliper bracket mount and that caliper has a 60mm piston bore! if you have bigger wheels and find the appropriate sized master cylinder for such a bigger piston, you can essentially run this setup with the 2001 mirage brake disc/rotor and pads as the brake disc dimension are same except the 1992 galant has a 4x114 wheel bolt pattern.
Also, knowing that the 2001 mirage brakes fit on our cars with slight modification, there additional threads in the older mirage forums of people upgrading to even larger brake setups, but they also have available options for the brake master cylinder and have upgraded to brakes such as those from Mitsubishi Outlander or Eclipse or 3000GT. but you'll have to do the research for actual fitment and clearance of everything.
Thank you and hope this information helps someone.