Latest mod installed today - MCA Traction Mod:
Installing on jack stands in my garage was not super fun...LOL.
Also, if you ever do this mod, do yourself a favour and do ONE SIDE AT A TIME. I.E. do EVERYTHING on the one side, then start the other. Trust me.
Haven't had a chance to really push it in the twisties yet (my favourite roads are currently cut off by flooding due to heavy rains over the last few days), but I took it through some of the spots around town where I've had some code brown moments with the back snapping out mid-corner and my first impressions are that it does what it says on the tin - puts the power down much better through corners and particularly bumpy corners.
Before, it felt twitchy and would snap into oversteer when the outside rear loaded up suddenly and the diff would shunt the power to that wheel, but now it's WAY more planted.
Helical diffs on FWD are friggin magic - when the outside wheel loads up, it just shunts torque to that wheel, tucks in and drives the front end around the corner. I installed a Quaife diff in my Tiburon, and it was insane how well it could put power down in corners.
With the BRZ's stock behaviour, I was having my doubts whether the same type of diff made sense in a RWD car. With this mod, I feel like it more progressively loads the outside wheel, making the diff behave better. The car feels like it has more of the balance it should have had from the factory as a proper sports car.
HIGHLY RECOMMENDED MOD, for sure!