Just posted and realize some is a bit redundant, I will clean it up in a bit.
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One thing Ford did was dial in some fun with the rear alignment, it works great up to a very high point but would induce high speed issues on a track and overall issues on a car setup to be far faster than stock on super sticky and wider tires like I run.
If you look at a typical FWD street alignment, not much front camber, quite a bit of rear, to induce understeer, it is far safer for the vast majority of drivers
FiST, more front camber, little rear, to make the car tail happy which is great fun and part of the love for this car!
Sorry I do not recall the exact numbers and those are not all they did, some of which may not be published.
Stiffer rear axle instead of adding a sway bar
Mild front bar
Possibly king pin angle which effects several things
Roll center
Bump steer
Ride height
Shock valving
Spring rates
And more
This was a pretty serious effort taking a lot of engineering and testing to get this car sorted so well for the intended purpose.
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As for me changing the rear alignment.
It was a great deal of effort to change it, difficult to tune it...So I researched what other similar car settings are stock and race modified and ended up setting it up very close to the a very fast SM class turbo Matrix I had built in 2002 and it is working incredibly well. -1.9 camber and 0.0 toe. My goal was -2.0 but -1.9 is enough and it allowed fitting 9" wide rear wheels under the rear fenders with some serious pulling and rolling effort to not move them much but enough.
-1.5 or so may of been enough but I wanted to ensure plenty of rear grip to induce high speed corner understeer, just a bit, which I can tune in several ways.
5-way rear bar if I run it, testing will show if needed
Bigger front bar
Spring rate
Ride height to a degree
Damper adjustment
Air pressure in tires.
Front toe, camber and castor
Wheel offset, effects scrub radius and more
Scales to corner balance
Bump steer, yet to be tested, it has little or none at the moment.
Later if a very good moderate cost 2-way coilover kit comes out I will give it a try as well, for now the BC race spec ones are quite good.
I am in the process of moving the camber adjustment to the strut knuckle from the top of the struts now as it is a better place to do it, I have to run wheel spacers to clear the coil overs so will have custom ones made once dialed in.
Since most of what I do will be impossible to provide data usable for others setups I am just offering what I am doing as an overall idea of what I am doing and why and then professional level links so you can see why I do such things and what you can learn about your setup for your needs.
Have a great day
Rick