There's a limit of how much weight being shifted with ride height difference, and I don't think GT6 simulate this well, there's something wrong when FF replica that I tuned without ride height difference suddenly can rotate much more than it would be in real life with extreme difference in ride height ( high front ), while the weight distribution is at 62/38, a 50mm difference won't send a lot of weight to back, even if it did, it won't instantly give rotation without touching springs, damper, toe and arb. In GT6, regardless of spring rate used or damper setup, using the ride height will always give the same effect, more rotation or less rotation. I experimented early back in 1.00 when making replicas, I was like this
when I found out about it.
What I was trying to get across was this : Don't depend too much on using ride height to fix a car handling problem as the 1st step, I would suggest to use it as last resort when all else fails, consider it as a final touch to complete a tune.
Most of the time,
a good spring rate tuning will do a lot to help a car drive better, and most of the time works better than using ride height. I always use equal ride height value when tuning, tune the best I can with spring rate, damper, arb and toe, I even use some camber to purposely reduce grip slightly. This forces me to tune even better and pick up certain handling traits not visible with zero camber.
Once done, if I still have rotation issue, I increase or lower ride height, usually I only use 1-10mm difference on PP tunes - with a well tuned car, 3mm can be really felt and 10mm difference is more than enough most of the time.
While on replica, I use whatever value to replicate real life car visually
Then I go from there, fine tuning some more, there are cars in GT6 with lower/higher front setting on ride height that actually gives level height on the car visually. The Clio RS for example.