Shamu

I'd drop the catback exhaust mods, shift knob, etc. Set of long tube headers, up rev tune, Get a set of good coil overs like Motons or JRZs. kW3 s are decent for a budget shock but arent close to good 3 way adjustables, nice 35 mm progress front bar, no need for differnt rear bar, oS Giken LSD, 34 row GTM oil cooler, set of real race seats like recaros, race tech or Sparco FIA certified, good set of harnesses, harness bar or rear roll bar, some lightweight 18 inch wheels with Hoosier r6s or Good Year RS dot race tires. Good set of brakes. AM performance oil pan, nice Momo race steering wheel, surge pump (to address fuel starve issue), Rear diff cooler. 4.08:1 final drive ring and pinion gear set. Lightweight flywheel, clutch, upgraded throwout bearing,, etc, top notch racing fluids. Use the rest of your money to stay on fresh tires and fluids.

Z isn't going to be a Z06 beater but it will be fun.