The BR6 master and booster were the Euro version until 2012+ when Jeep made all NA and Euro master/booster the same. I haven't confirmed if the J8 uses a different master yet, as I believe the rear calipers are different than production. On the 2012+ I find the best upgrade is simply bleeding the crap out of the system, the pedal is mushy and crappy as received. A power bleeder is ideal, but old-fashioned way works fine too, just run all old fluid out. A good trick for swapping brake fluid is take a plastic squeeze bottle with a little length of hose (I use vac line) and suck old fluid out of master. Turkey baster works good too, you get the idea. Once old crap is gone pour in fresh and bleed through calipers until fresh comes out. Start with right rear, then left rear, then right front, finally left front. Jeeps come with DOT 3, don't bother upgrading to DOT 4 the only difference is higher temp capability which is a waste for Jeeps. DOT 5 IS NOT COMPATIBLE with DOT 3 and once again a waste of $$ for a Jeep. In testing it has been shown that generic DOT 3 is almost identical to Mopar, Ford, etc. so save your $$ and buy from Autozone, O'reilleys, etc.
LoD front Ace Engineering rear Xenon fenders Rockhard skids EVO Rockstars Mickey Thompson Classic Beadlocks Goodyear Fierce Attitudes Spending as fast I can!