Help tuning my honda civic 1997

Hi all

Im fairly new to tuning. Iv made a few cars that have worked well. These were fwd tunes. Iv started doing rwd, made a e30 m3 which is pretty good but im struggling with my civic. Its in c class and rwd. Iv been tuning round Silverstone full circuit and im getting low 2.24s. The problem is on entry to a corner the rear end is stepping out on long bends and also as I let off and down shift into the corner then turn in. My diff is set to 27 acc and 15 deacc. Iv messed with bump and when I stuck them both to 1.0 I actually gained a whole second round the track? Im running high rebounds. Anyone tell me what could be going on? Any help would be much appreciated.

Thanks underdog

Could it be rear toe? Iv got it at 0.1 toe in.