rx7london

hi ive got a to4 single turbo kit on my fd not shore which turbo it is but i think its time 4 a upgrade i was looking at the hks t51 kai or t51 spl 56T AR 1.0 or maybe a gt42r but its a road car so dont want a turbo with extreme lag i no these are all big turbos so there gonna be laggy i would like close to 500 true horse power at 1.2bar at the wheels on 97 octane pump gas wondered what rpm these turbos would get on full boost at which one would you guys recommend also how can i tell if these fit on my car manifold etc.
thanks
john