Came across this disc conversion..

[06YarisRS]

Originally Posted by WeeYari

Hard for folks to chime in when nobody has experience with this kit. Someone contemplated this exact kit a while back but that thread never went anywhere. The general consensus is, for this car, rear discs are primarily a cosmetic mod. No real braking performance gains to be had. Lot of money for cosmetics.

Yeah, I'm really fence-sitting on this one after further consideration. I think it would look great, but I'd need more empirical evidence that it would help with braking in any measurable way. I can't see how the braking would be balanced as the braking system would be designed to work with a specific piston (rear wheel cylinders) surface area and stroke. I'm no fluid dynamics engineer, but logic tells me that the larger caliper pistons would have to affect the dynamics. I question whether or not the company would do the necessary research to tune the braking accurately. I think you're bang on, WeeYari, when you say no one has experience with the kit, therefore folks might be reluctant to attempt the conversion. Again it would look great, especially with my 16" narrow spoked wheels, IMO, but there are too many unknowns. For my own setup, probably a good set of pads, like the Hawks, would be the best approach. Maybe, even the SE 275mm discs, xD or Corolla caliper and master cylinder would be a good option too. Despite all of the aforementioned, I'll be watching youtube and checking the web occasionally for anyone that has done the conversion. I'll keep this kit in the back of my mind.