Ah yes the great debate. Read up on it stickied here
http://www.club-tc.com/forums/forced...ercharger.html
BTW... More boost is safer on S/C not turbo apps. It is all about how the boost is being made. The TRD can boost up to 10PSI w/ no piggyback or internal work and not kill your motor. A turbo setup has to have a piggyback and good tuning on boost over 6PSI. It's all in the sticky.
TRD S/C $1850
TRD Toyota/Scion Parts Accessories from Sparks Toyota/Scion
9, 9.5, or 10PSI pulley about $100.