xero : the internal one is comes already with the turbo unit itself..the external one is..outside.
http://images.google.com.my/images?q=tbn:VFE4lSizujz9SM:www.madpsi.net/Projects/MR2%2520(SW20)/Madpsi%2520-%2520Pouyas%2520MR2%2520-%2520TiAL%2520external%2520wastegate%25201.jpg
external
internal
http://www.tuneupchile.cl/performance/wastegate%20en%20pagian%20de%20standar%20boost%20controller.jpg
http://images.google.com.my/images?q=tbn:VFE4lSizujz9SM:www.madpsi.net/Projects/MR2%2520(SW20)/Madpsi%2520-%2520Pouyas%2520MR2%2520-%2520TiAL%2520external%2520wastegate%25201.jpg
external
internal
http://www.tuneupchile.cl/performance/wastegate%20en%20pagian%20de%20standar%20boost%20controller.jpg