Guy with your set up you are going to make a setup that you will not like and is dangerous. First of all what you are saving in cost is going to cost you in the long run. Smaller brakes will wear fast and are less force to stop you. The heat fade is going to cause you problems on stopping.
If you are cheapening out you are not doing yourself any favors. You might not want to hear this. You really should look at the higher performance vehicles They all have large brakes either disc brake or drums, now why would they do this??? Because with your thinking and pursuit of this change from 10 to 9 does go against all logical thought patterns.
Sorry if I'm seem of being brash about this. You seem to past up my first post. But I'm glad of one thing that you live far enough away from any of my family. But I might meet you by accident. Because I drive a truck and come in the area you are. My only blessing is that you will that battle. Now you have been fairly warned about your actions. You can do as you wish. You already have a weak braking design with 33" tires.
A 89 yj with a 4.0 aw4 sye out of an 92xj. Now the hard part is done time to get it up in the air just a bit. Working on 8.8 with 3.73 and lsd for the rear. and new D30 hp with 3.73 .
For those who have not figured this out I'm old school but can handle the new too.
im just cheap, and cheap makes you creative.