Possible oem BBK option.
 

I have had terrible luck trying to find TT rear calipers for any reasonable price so i went looking for some other options and i may have found something. The cadillac ATS has Brembo 4 piston fronts and 2 pistons rears that appear to be nearly the exact same size as the Supra TTs.

Fronts :
Supra TT -
diameter = 323mm
nom thickness = 30mm

ATS:
diameter = 321mm
nom thickness = 30mm

Rear:

Supra TT:
diameter = 324mm
nom thickness = 16mm(not certain on this one)

ATS:
diameter = 324mm
nom thickness = ?? not sure either, but i assume they would be pretty close too the supras.

Going by these numbers, we should be able to use the ATS brembos on our cars with the TT rotors and possibly pads as well, the only thing required would presumably be a custom mounting bracket and brake lines. Another bonus would be that these calipers look pretty good, and being that they're from a GM vehicle they're pretty cheap, i've seen them go on ebay for around $400-500 for a full set.

I have ATS-V 4 pot rears on my 96 SC300 paired with ISF rotors. You will need a custom bracket. There is an old member on here who made them.
Mine might be up for sale soon, putting it back to stock for sale.

Are those the 320mm or the 355mm calipers?

Deals for rear TT calipers are out there.....just need to be quick when they are available.

hi, did this ever pan out? Were you trying to install on the SC300/400 or SC430? Would really like to hear your results or any info you found out.

Correction BiGEZ. You have CTS-V 4 pot rears! Im your Huckleberry!

Personally, I bought the Jeep kit, and I'm going to have monster calipers and rotors as they are using all isf rotors and jeep SRT8 calipers.

Are you making the brackets yourself?

Don't do it. Never got mine to fit properly, there was always a 'scraping' noise. A total waste of money, I went ahead and had the calipers painted.

Suprastore.com now offering brackets to mount the 07+ LS460 calipers using ISF rotors, just another option. They will be releasing the rear brackets soon.

Took me awhile to find that on their site...

https://www.suprastore.com/xatsulsbrcau.html

That says it fits the SC430, not the SC300/400.

will these fit over 17" wheels or only 18" and up?

They fit the SC3/4xx perfectly, does not need the roll center adjusters to fit on the SC. Those are for the GS. I tested fitted this setup on my 99 SC400 and it is a perfect fit.

My familiarity is limited to what they say on the page, so I'll trust your firsthand experience... Does Supra Store know they fit the SC300/400? And if so, do they have some reason for not advertising that selling point?

Another option is the 07-11 GS350 calipers and rotors with a custom bracket for the bottom caliper mounting point. The top bolts up.
I just completed this upgrade on my 01GS430. The GS350 rotors are 334mm while the LS400 are 315MM. I tested fitted them with the brackets on the SC and they fit great.
Pics of the setup on the GS.
https://cimg0.ibsrv.net/gimg/www.clu...e35d9001ee.jpg

https://cimg5.ibsrv.net/gimg/www.clu...c7f2f0866c.jpg

These are the bracket needed. I have the drawings if anyone know a good Machine shop willing to make them.