i highly suggest going URD s/c! for the money spent you get more gain... if your going TRD blower for warrty. If you start modding your going to void your toyota warrty anyway. SO take it from someone who has one of the most modded out trd xrunner...GO URD. plus x-1 comes with it..
Well... if you want to break it down.
Here are the facts, based on Gadget's personally built & tuned truck (actual street results have not been seen), and as close to equivalent as we can get.
Stage I = Supercharger, Intake, Fuel Pump, X-1TRD setup equivalent to the the URD Stage I
TRD S/C - $3500
TRD CAI - $350
X-1 - $1300
Fuel Pump - $170
TRD Stage I - $5320 - 328rwhp (6psi - ABP) - $16.22/hp
URD Stage I - $5895 - 337rwhp (7psi) - $17.49/hp
Stage II = Stage I + Pulley, Headers, Y-Pipe, ExhaustY-Pipe = $469
CBE = $529
DTLT = $514
TRD Pulley = $89
URD Pulley = $79
TRD Stage II - $6921 - 351rwhp (9psi @ 6200rpms - Dakota-rt-2a-xr) - $19.72/hp
URD Stage II - $7486 - 380rwhp (8.5psi) - $19.70/hp
We will use the APR Stage II kit (2.7" pulley + 7th injector) for the TRD Stage III. We don't have any reported dyno numbers from this kit yet. But based on my truck with a DynoDynamics dyno (that reads low) and 1/4 mile MPH speed, I should be about 340-350rwhp on a dynojet. Lets call it 340rwhp on the stock pulley with the 7th injector. The 2.7" pulley is capable of producing at most 10.9psi of boost (per the engineers at Magnuson, 8.3psi on the stock pulley, 9.75psi on the URD pulley). We'll say 10psi the avg under good conditions. I peak at 6.5psi. So add 3.5psi at 20hp per PSI (again per Magnuson with supporting mods), that's about 70hp gain. That paired with a race tune on race fuel (as the URD Stage III kit was done). Say you only advance 2.5* timing advance at about 4hp per degree, so an extra 10hp. So about 80hp gain (over stock pulley). So we'll call it 420whp (actual results will vary!)
Stage III = Stage II + Pulley, Race Tune, Grill for URD (as stated on URD's site)
APR 2.7" Pulley = $389
APR 7th Injector - $620
URD Pulley = $79
Grill - $140
TRD Stage III ~ $7930 ~ 420rwhp (10psi) - $18.88/hp**
URD Stage III - $7705 - 422rwhp (8.5psi) - $18.26/hp
*note prices do not include shipping
**Prices/Numbers are only estimates!!