you're looking at 8k at least.

you have to think about all the little parts you need that will cost.
fuel pump, lines, filter, fpr, injectors, fuel rail
clutch, axles, Differentials because you'll probably break stock
mounts, pistons, sleeves, rods, bearings
turbo components, turbo, oil lines, water lines, intercooler piping, wastegate, BOV and intercooler.
ignition parts
ECU, boost controller

and then if you get all that you can't run it at the strip because it's too fast so you have to get a rollcage and some slicks

Same thing goes for the autocross, which I don't think you plan to do much of with 20+ psi of boost.