It's not just the R8 Ultras - it's something that seems to be affecting the MR cars in general, especially online.
There's too many reports from people who usually like cars that oversteer (ie Yellowbird) who say that there's too much oversteer on MR cars when cornering. Cars are loosing traction when not being pushed hard at all, even at low speed.
We did a load of testing and some very strange results came up - so stange that it left us with no doubt that whatever PD has done, is just not right.
Reason being, when testing all the other drivetrains, the same philosphy works though-out them, and has done since 1st gen physics on GT5 - still works now. The only time it doesn't work is now with MR cars.
Combined with the reports about MR cars - that's not a coincidence.
Look at the FXX in free run - totally stock, rolling acceleration from 2nd gear in a straight line. It manages to put near 800hp down through sports hard, without much of a fuss(???) - which is so not right, but floor it in 3d or 4th whilst cornering - adious amigo, she's gone.
We tested the R8s online and some circuits were worse than others, but generally any kind of cambered corner, even at ridiculous low speed and it was game over for the outside tyre.
Eventually we sorted it (without ballast), but this was using methods so extreme, it just re-iterated how wrong things are because none of the other drivetrains need anything extreme, in any area of setup, regardless of power/weight/grip.
We'll have to wait for Polyphony to change it - or you resort to ballast or highly extreme / unusual tuning for some tracks.
The front end is way too responsive, it turns so quick the back end can't keep up. Normally this can be sorted with things like diff / ride height / readdressing the balance through springs, dampers and roll bars, but depending on track and car (and remember, supposedly PD has built in other variables into GT6 like temperature), it'll change how far you need to go.
With some racecars, a quick and easy fix is to use a lower compound tyre on the front, ie sports soft on front, racing hard on rear, racing hard on front / medium rear - this gave immediate results on problem tracks like Apricot Hill, but other circuits this wasn't necessary.
Either way - there's nowt we can do to generally fix this - it's up to PD to get the online MR physics better balanced..