Are you having issues with it losing stability while braking, especially braking into a turn?
I've been playing around with it off and on since it first appeared in the LCD and its a quick car for its age/considering you can't add downforce, but the stock tune is terrible. I'm no Praiano by any stretch, but try this:
Suspension:
125 135
8 2
36 36
47 47
2.50 2.40
2.5 2.3
\/0.04 /\0.20
LSD of 18/10/25 You might try much higher/lower brake sensitivity (last number in lsd) to see if it helps with destabilization while braking, that's one thing I've yet to try.
That's with a car with pretty much everything done to it: all weight reductions, all permanent engine mods, medium/high turbo, etc, etc. No ballast; neutral brake bias. Oh, and this is on racing hards for Sarthe, prob should have mentioned that earlier. I've not really played with it at Tokyo/600pp so I've no idea how to set it up for that race. Still need to be a little careful on the throttle in 2nd/3rd around corners if in the middle of the rev range, and if the rear is kicking out too much for your liking just soften the rear a bit.
I've got 4-5 different tunes I've been working on with this car and just can't get high-speed braking stability nailed down. Not sure if it's the high center of gravity, the low weight, no downforce, me not knowing what I'm doing (probably this one, lol) but if you slightly trail-brake in the braking zones it makes the car much more stable. Other than that its not bad. Capable of 4:08 laps at Sarthe reaching 190+ on the straights if the transmission is geared properly. Quicker with a better driver/tune, though zero downforce makes the twisty sections quite a bit slower than normal.
Hopefully it works well enough to tide you over until one of the good tuners tackles this car.