forget the 0.86 2871's i have used a few and they are pretty average, require 20-22psi to make decent power over the smaller housings.. even then the extra top end is not worth the lag...
Put simply we had a GT2835 ext gate kit (HKS) making 288rwkw, the GT2871R 0.86 was laggier and was 15-20rwkw shy on the top end aswell....
Best track day turbo for a SR20 is a GT2860RS with decent cams to extend the top end, a SR20 with GT2860RS should pull 220-235rwkw on a std bottom ended but cammed engine no worries at sensible boost.