Hello dudejo, welcome to the Settings and Tuning forum. Your first posted tune is an excellent attempt but I feel I must share my observations to help you, so you can help others. You have made several statements that run contrary to current GT4 theory, it isn't to say you are not right, you just would have to back these points with test results if you want to be in agreement with the other tuners here.
First and most glaring point, raising front spring tension in relation to rear almost ALWAYS induces understeer. To understand the concept, imagine the stiffer spring is tilting the cars weight onto the set of tires that are sprung more softly. The actual reason is more complex, but the illustration serves in simplicity. The only real reason raising front springs will make the car turn better would be because the overall suspension is so soft as to loose traction through bounce unweighting. In this scenario, more stiffly sprung turning wheels would probably grip better, hence the sensation of induced oversteer.
Secondly, ride height never affects tire wear unless the ride is so low the chassis is contacting the ground. On high powered cars (like the Minolta 88CV) the drive wheels will start to burn under reduced traction, this usually happens only at speeds above 180mph. You can see the evidence of this if you have your B-Spec driver drive the car on the Sarthe course with the long straight. When you set your view to the rear, you will see sparks trail away from the car. Those are representive of pieces of chassis, and if the simulation were complete, your car would be getting lighter.
Additionally, have you tested your theory about downforce? I have tuned approximately 200 GT4 cars, and although every one of them has been a learning experience, I have not found a single instance where lower downforce translated to reduced lap times, and the time lost skidding onto the grass can be maddening. That is not to say it isn't so, I just recommend you test.
Also, most tuners agree that the damper settings are relative to the car, which is to say bound 8 on a Aston Martin Vantage is much stiffer (or as Duke might put it "less inclined to move") than bound 8 on a Toyota Vitz, which is a much lighter car.
I could suggest your damper settings are too low, but, by all means, use what works for you.
In terms of LSD, I have seen in my own experience that the removal of LSD on the front of 4WD cars and FF cars actually increases turning radius, usually not a good thing. I will concede that these powertrains need little LSD, but to eliminate it entirely could hurt you.
Finally I recommend you read some of the technical related threads in this forum. Many tuners, engineers and race car mechanics have contributed to our store of knowlege and ideas. I will run a search and include links of those I think are most helpful. You should start with the stickied ones by //M-Spec, Greyout and Scaff. If you want to tune competetively, they are definately worth the time spent.
Is suspension Tuning Backwards
noob question about ride height
sukerkins guide