Originally Posted by: NightDriver7800 
So, I didn't actually review your spreadsheet, so here we go. :)
I quite like what you made. It's possible to get a very good base tune with the values provided. However I ran into some issues.
Out of the box, the cars will understeer too much for my liking. So I'm trying to make incremental steps towards oversteer in my suspension setup. I've got a couple questions.
Softening the front in mid-engined cars creates the oversteer effect but also makes them a bit too loose. Is it ok to increase decel lock in this situation? Interestingly, the standard decel lock values provided seem way too low for rear and mid-engined cars. The Porsche 911 usually comes from the factory with more than 80% lock, for example. Max suggested decel lock in the spreadsheet is 30%, I believe.
Another question is, when I want to change something in the suspension, which setting is it advisable to change first?
Finally, worse tires (usually stock but also street sometimes) tend to have less grip and also feel boat-like compared to race or even sport tires. Would it help to simply stiffen the suspension to make the car more responsive?
Thanks for the feedback I appreciate it alot.
Firstly any tune calculator or spreadsheet will never deliver a perfect tune. It will always need further fine adjustments. As a base setup having understeer is a good thing, it will give consistency. If you are prefers more over steering car then you can try inverting your ARB's. But as a rule of thumb only adjust the end with the issue.
For example never create over steer in the rear to combat understeer on the front.
Additionally decreasing front height, increasing front spring, bump or rebound. Also increasing front tyre pressure are things that will add responsiveness to the the front. Along with Toe, but as a last resort. Your break balance can also change your car characteristics. Making it more rear ward can help.
It seems unusual to have over steer from decreasing spring in the front of s mid engine car. If anything it should be understeer. I would advice looking at your ARB'S again and/or bump rebound setting. Front ARB controls the car on entry to mid corner and the Rear ARB controls mid to exit corner speed.
It is usually advisable to adjust springs first if changes are required. In small increments of around 10-20lbs. Stiffer for flater tracks and softer for bumpy and track with elevation changes.
With the Diff Decel it takes a bit of playing with, each car can have a different sweet spot. The idea behind low diff settings is that it allows the car to rotate better, to high not enough rotation, to low to much rotation. Hence the playing around to find the best setting.
Tyres should always be between the 32 min and 35 max regardless of compound. Just adjust to find the settings that give you the best feel.
Hope U have answered all your questions dude, let me know how you get on in future 😁👍