GS300 TURBO

im new here.
i have a 2005 GS300 and want more HP. probably about 300 HP would make me happy.
what do u guys think about this turbo kit? 
http://cgi.ebay.com/ebaymotors/2JZGE-IS300-SC300-GS300-SUPRA-GT70R-TURBO-CHARGER-KIT_W0QQitemZ320200529072QQihZ011QQcategoryZ33742QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
 
do i need more than this kit? do i need to make any internal modifications?
any feedback would be nice
thanks.
 

Never seen it done. You can probably run a turbo on stock internals just with only about 15psi.