You can certainly go a bit faster with that turbo. You've got room for 2-3 more degrees of timing, room to go leaner and probably a few more psi with better gas.
I wouldn't go 42r. A gt4094 got my friend's full weight/full 3 inch exhaust 95 gsx (just a/c and power steering removed) into the 9s ([email protected]) without nitrous using dsmlink and a stock 2g maf (fake maf feature). That turbo should put you into the 9s easily since you weigh less and it wont be too laggy. He ran that at around 32-33 psi, 12 ish on the air fuel ratio and around 20-21 degrees of timing (c16 of course).