Hi, this was a project car of mine a while ago. I've been away for a while though, and my race mates have moved on to a different category of car now.
However, this is where I ended up with the
'00 version.
Suspension
Ride Height: -15/-15
Spring Rate: 5.6/4.5
Extension:-- 3/3
Compression: 5/5
Anti-Roll:-- 2/4
Camber:----- 0.5/0.0
Toe:-------- -0.10/0.20
I didn't bother installing a custom diff, as apparently the stock one is pretty trick. A custom diff coulld probably extract a bit more power and grip. I only boosted power to 355BHP, and dropped the weight to as close to 1250kg as I could. It drives ok, but it's still not properly sorted. And I'm now having something of a panic attack because I think I've been reading and recording EXT and COMP figures incorrectly. I also think I've transposed SRs too

I checked some real world figures, and I think the ride height might be a bit off too.
Try the following. I can't get near my PS3 for a day or two, so I can't verify if this'll work or not, sorry.
Suspension
Ride Height: -21/-17
Spring Rate: 4.5/5.6
Extension:-- 5/5
Compression: 3/3
Anti-Roll:-- 2/4
Camber:----- 0.5/0.0
Toe:-------- -0.10/0.20
Hope you have some success, as I'd like to finish this car off. Let me know how you get on and if any of the above is of use...
{Cy}