E36 Track Spring Rate / Setup Suggestions

[f0xy]

Hi - I have spent a week searching on here and found some very good posts regarding what setups people are running for track-only cars, but I'm still uncertain on which way to move forward with mine. I will try to outline the car in brief first - this is track-only, not street driven...

Car - E36 Sedan, ~1150kg/2500lbs
Engine/Transmission - 3.0L 290-300hp/270lbft, ZF S5D-310Z 5 Speed, 188mm Kaaz 1.5 Way LSD (3.64 Ratio)
Suspension - HSD Monopro Coilovers, 10kg/mm Linear Front Springs (560#), 10kg/mm Progressive Rear Springs (560#). Camber/Castor Adjustable Top Mounts. Approx 70-80mm Droop F+R. Hardly any preload on the front springs (Both Adjustable On HSD)
Bushes - Completely Polybushed Front + Rear, M3 Trailing Arms, M3 Front Hubs, E30 Front Wishbones, Solid Mounted Rear Subframe, Camber Adjustable Rear Arms
Sway Bars - 25mm Front (To Wishbone), 15mm Rear - Both OEM BMW
Wheels - 17x9 Square
Tyres - 255/40 Semi-Slick
Alignment - Front: -3.5 Camber, 0 Toe -- Rear: -3 Camber, 30min Toe In (Total)

The car drives well, but feels soft, and lacks the turn in it used to have. This seemed to change when I moved to a square setup with the wheels. It also seems to roll to much. Balance at speed feels OK, its easy to control on oversteer, when it happens.

I understand the rear spring rate is less at the wheel, due to where the spring is located - I'm unsure whether to change to a linear rear spring (and increase the rate), or to change to aftermarket sway bars, or both?

Any suggestions welcome.

[MINIz guy]

Stiffer front sway bar and stiffer, linear rear springs should solve all of that. I ran a 32mm hollow front sway bar and 12k rear springs, on slightly less tire (245 RE71R), and would never describe my car as soft on the track. I don't think you need as much rear camber, and I would dial out the toe-in to make it turn in better.

[bostonaudi]

Turn in response also highly dependent on tires. What exactly are you running?