I'm thinking that I'm confused right now
I didn't start having this problem until I changed tires but my tire change was to a different size. I'm running 225/45 & 245/40
I've had different pads and rebuilt my calipers while on stock tires and never had this issue. I've ran in to other issues like boiling fluid from running the wrong brake pads but not the issue we're having now. For me it started after changing tires.

 

I have never experienced this problem despite running different size tires on my07.

235/45/17 255/40/17
225/40/17 245/40/17
245/40/17 245/40/17
255/40/17 255/40/17

I had some inconsistency but that turned out to be the calipers needing a rebuild.

 

Its popping up in the STR thread in the Roadrace/Competition Forum.



I'm going to look at my front calipers tonight and see if I see anything goofy.

 

I had that issue at last weekends autocross. In a section with heavy braking over bumps.

 

If not fluid.....

Could the tire shop have gotten some type of grease for chemical on the rotors? Maybe the pads have glazed over the rotors reducing the friction and stopping ability. The pedal would feel the same but the car will not stop.

Does the S have a proportioning valve? I've had that go bad on my 4Runner.

Good Luck

 

The issue is, it will stop well in one corner then take a lot more pedal pressure to stop in the next. Seems to be an ABS issue. I am running stock size tires.