Ryan the above questions really need to be answered...
But a rough estimate for a full stage 2e intercooled system for your lexus
SC400 would go 2 ways:
-twin turbo setup....streetable with the high horse power kick.
twin turbo setup,fast spooling pair of turbos.Huge amount of hp.Larger FMIC
and huge flowing intercooler piping.
approx.5000.00 us funds installed and tuned
-Super single setup, still streetable but on the boarder of being hard to
control on the street.
*Precision Turbo T64E or T64 Big Shaft
(T64E is rated at 700 bhp)
*Tial 45mm external wastegate
*Tial 50mm b.o.v
*FMIC Spearco core, ES custom end tanks. 2.5"in and 3"out to throttle body.
*8 psi system with stock fuel system
*Vortech- FMU is simple and work fine with 8 psi.
*Custom Driver side header
*304 ss Midpipe
*Custom 3" Downpipe
* Lots of misc parts.
The price estimated for about 5-5.5k us funds, it will be over 300 rwhp with
the nice sized turbo, the V8 potential is endless.

Options;
-wolf3.0 v4 standalone system .comes with electronic boost
controler,security,turbo timer and many many more options.
-larger injectors,intank fuel pump and regulator
-act street strip clutch..you'll need it to put the extra whp to the ground.
for the show quality the kit can be fully ceramic coated and polished