Just bought a new 06 Trailblazer LS w/ the 4.2L inline 6 Its silver blue metallic which isnt the most macho color but it was the best deal so i went w/ it. I'm getting good mileage but would like to get more so I've got some questions the performance guys out there. Is there a way I can get about 20 more horses and some more torque out of the engine for around $500 to help give me better gas mileage. (I've looked at cold air intakes but there doesnt seem to be a lot for the 06 trailblazer on the market now) Just curious too.. Is the four speed automatic that comes standard the same that comes on the 5.3 and the 6.0L? I would also like to put a nice sound system in there if anyone has any suggestions for that too.