These are just tuning suggestions based off how I tune, everybody may tune differently or have different ways to use adjustments in relation to each other to achieve a goal, this is just how I do it...
Most settings will impact each other, and some adjustments are to counter side effects of adjustments used, usually stuff that improves cornering ability can hurt straight-line performance.. Ideally for going in a straight line and taking a corner the suspension would adapt the wheel angles and suspension, as both would have different settings. We have to compromise between straight-line performance & cornering performance when tuning a car.
Ride Height
The problem:
Lower rear then front.
Raising the rear ride height will raise the COG on the back end. Lowering the height lowers the COG, the higher the COG the more the weight in the rear end will want to swing out. Too much and you overload the outside rear tire. Too little and you don't get enough rotation (under steer)
You may have been mislead by the game being glitched before a certain update where ride height adjustments were kinda reversed and all together not working right. Higher setting raised the car but it acted like it was lowered, weird NFS Shift stuff.... Its been fixed in GT5 with an update, the whole game just feels much better.
Suggestion
You need to raise it to get more rotation out of your back end.
Raise the rear ride height to equal to or a little bit above the front
The ARB
The Problem:
Its set up for a FF or FR, NOT a Mid-AWD The ARB need to be stiffer where the most weight is, as its the weight they have to fight. More weight = bigger fight. Your ZZ has nothing in the front, but running higher front then rear ARB (possibly this is working with the high front toe out and the two together are misleading you into believing they are tuned right when they are not.)
The Suggestion
The rear needs to be raised and front lowered Because the rear has the engine weight the front is light.
Toe
The problem:
Your front is too loose with suck a high setting and no rear toe to stabilize.
The Suggestion
Since we have made the rear end more more prone to rotating, it will want to swing out under power making getting on power less stable, the toe in on the rear will help compose the rear end when we are on power aiming for the exit.
Add much more positive toe (Toe-in) in the rear, & bring the front toe closer to 0. When your braking and the front is loaded your fine, but when the front unloads and the rear loads up you run into trouble, so keeping the toe out on the front should be alright to some extent as long as it doesn't get unstable after tuning the ARB for M/AWD. The rear as you have it is good for straight line running and not suited to a AWD a better range for you would be 30 to 45 toe in on the rear.
The diff
The problem:
Way too tight
Your experiencing understeer under acceleration and have raised the front and rear accel , both will only make the car fight harder to go straight under acceleration. The front end INSANE double what the front should have for accel. The natural characteristic of the FF platform is to understeer under acceleration as the wheels powering the vehicle are also turning it. A AWD ride shares this tendency thankfully our diffs can counter it. Imagine all 4 wheels spinning the same speed all the time, not a easy thing to turn. Your Diff is entirely out of whack
Suggestion
Lower both the front and rear accel, again the front more than the rear. A good range is 15 to 25 front and 30 to 50 rear, however you lower it on the end that refuses to rotated under acceleration. Since your having understeer on power issues I believe 50 in the rear to be too high and something closer to 32 to 38 would be a better place to start fine tuning.
Possible areas to address
The springs seem crazy stiff for such a light ride possibly limiting the impacts of tuning adjustments way too much.
Under acceleration the front being unloaded coupled with when accelerating out of a corner we are turning we need those front wheels to turn the car the high Spring rates may just restrict the suspension to the point of being un tunable.
The Dampers, softening up the rear a bit may make the rear end take the corner better apex out. Since pretty much up to apex your on the brake so the rear end is unloaded while the front is loaded, at apex you transition from brake to gas, and in doing so the front unloads and the rear loads up, its at this point you have your understeer issue. Making the rear softer a bit may make the transition more smooth and less "shocking"
The Camber looks good, might help with a little more angle in the rear.
just kidding. But, After reading this I am curious as to how it turned out. If I had a ZZII I'd give it a go too.
