So I recently installed the ST205 Brakes on my ST185 and wanted to dispel any myths about it. For this project I bought a set of used front and rear ST205 calipers and pads(~$600). The IS300 front rotors new from Autozone(~$80). The rear rotors from EBC; sourced overseas (~$275).
FRONT: For the front the calipers need about 4mm cut off of the mounting brackets. The calipers are not threaded either so I had to use a wrench and some tape to hold the nut on while I tightened the caliper down to the hub. The IS300 rotors are 5x114 pattern so I used my 5x100 spacers as the guide for drilling the rotors. Once I got 2x opposing holes drilled I bolted them on to the rotors to better guide the drill. The bore on these rotors is 60.1mm and the ST185 is 54.1mm so I purchased an set of hub bore rings that I hammered in from the outside to center the rotors and prevent oscillation. Once drilled I found it is easiest to bolt the bottom caliper nut first and go through the dust shield for the top one. Bleed the brakes as normal and the front is done.
IS300 (290mm) vs ST185 (278mm)
REAR: For the rear there is no modification needed to the caliper or rotor as the ST205 is bolt on to the ST185. The only modification I had to do was bend back the dust shield as it touched the rotor. Once removal and reinstallation is complete, bleed the system as normal.
ST185 (285mm?) vs ST205 (315mm)
ESTIMATE: I would say from the seat of my pants feel on these that they are maybe 20% or less better than the ST185 brakes. They look pretty cool and feel more responsive at first touch than the ST185 ones. The overall stopping distance 30-0 and 60-0 seems shorter, but I really don’t have time to measure it out. Overall I'm happy with it and would do it again.
FRONT: For the front the calipers need about 4mm cut off of the mounting brackets. The calipers are not threaded either so I had to use a wrench and some tape to hold the nut on while I tightened the caliper down to the hub. The IS300 rotors are 5x114 pattern so I used my 5x100 spacers as the guide for drilling the rotors. Once I got 2x opposing holes drilled I bolted them on to the rotors to better guide the drill. The bore on these rotors is 60.1mm and the ST185 is 54.1mm so I purchased an set of hub bore rings that I hammered in from the outside to center the rotors and prevent oscillation. Once drilled I found it is easiest to bolt the bottom caliper nut first and go through the dust shield for the top one. Bleed the brakes as normal and the front is done.
IS300 (290mm) vs ST185 (278mm)
REAR: For the rear there is no modification needed to the caliper or rotor as the ST205 is bolt on to the ST185. The only modification I had to do was bend back the dust shield as it touched the rotor. Once removal and reinstallation is complete, bleed the system as normal.
ST185 (285mm?) vs ST205 (315mm)
ESTIMATE: I would say from the seat of my pants feel on these that they are maybe 20% or less better than the ST185 brakes. They look pretty cool and feel more responsive at first touch than the ST185 ones. The overall stopping distance 30-0 and 60-0 seems shorter, but I really don’t have time to measure it out. Overall I'm happy with it and would do it again.