"The Purple Stuff" (Castrol Super Clean and others) does strip paint even inside the engine compartment. But from what I have experienced is that it attacks non-clearcoated paint quickly (though I am sure on CC'd paint the CC takes the damage and not the basecoat). I know on mine the engine bay is NOT CC'd and CSC made quick work of taking half of that paint with it.
For bare aluminum parts, I use Eagle One Aluminum Wheel cleaner (for machined parts) or Etching Mag cleaner (for cast parts), but take great care in where you spray that stuff...the mag cleaner is, afterall, an acid
Welcome, downwardly mobile yuppies, to the dawn of the Age of Nefarious.
1993 SSEi - FrankenJinx - dead and gone.
1994 SSE (136K strong) - 180* t-stat,HD alternator, most unequipped SSE on the club, XM radio, Kenwood CD/MP3.
2006 Chevy Malibu Maxx LTZ - Custom 2.25" manifold-back exhaust w/FM-80. Probably the only Maxx with this system.