currently i have a whiteline handling pack + rear diff brace + front camber kit installed on my ER34, running on stock shocks and tanabe variable rate springs and toyo trampios r1r hybrid tyres.
i've only ever used whiteline products on my cars (full works pack on my wrx) because jim and the gang are top blokes and i've always got great deals. so i can't comment on them vs aftermarket gear.
track performance is fantastic once you've dialed in the right settings. currently im running the recommended castor settings, 1.75deg negative camber in the front, hardest rear bar and close to softest front bar settings.
initial turn in is fantastic, nuetral to slight understeer coming out of the corner and predictable througout. body roll is not totally "flat" through the corners but that would mean sacrificing my street ride.
can't afford coil overs at the moment, but im not really fussed either, the way its handling now is great. should comment that spirited drives through the national park and such can get very bouncy but im really happy the way my suspension handles it. very compliant. says ALOT for a decent set of variable rate springs.