I figured I'd share the list I have over on .net with you. Special thanks to PenguinPIE and several other members from .net for a majority of the info Intake: The stock air box is highly restrictive. Freeing this up would provide more air for combustion and increase power output Cold Air Intake Injen >> AEM Rebel Autoworks (RAW) Advanced JDM >> Short Ram Intake K&N Typhoon 2.4 specific >> GM Performance Parts >> AEM >> Z-spec/RSM Racing >> Weapon R >> Air box mod Intake Manifold Hahn Racecraft Vulcan Turbo >> Kinsler Fuel Injection (optional upper rail kit) >> Exhaust: The less restrictive an exhaust setup is, the more power will free up from an engine. Our 2.4 stock exhaust system is decent (has 2.5" piping), but it is restricted by the header, cat (in the downpipe), and the exhaust section from rear wheel back (which becomes 2.25" piping and has a restrictive muffler) Header (Exhaust manifold) Long Tube (high-end gain) Weapon R Race Header (with downpipe, no cat) >> JBP Vortex Header >> OTTP long tube header >> Mid-length (mid gain) ZZP Midlength Combo (with downpipe, optional cat) >> SLP Combo (with downpipe, cat) Vibrant Header Combo (with downpipe, cat) OBX Pacesetter Header Clear Image Automotive Header >> CTI Race header (optional cat) >> Shorty (low-end gain) CA Header V1 (not produced anymore) CA Header V2 >> Shiny-Hiney (identical to CA V1) >> DC Header Hahn Racecraft GM Performance Parts Stock Extruded and Honed BADMAB Industries >> ZZP Header >> Turbo (for turbo applications only) Vulcan Turbo Downward Manifold >> Vulcan Turbo Equal Length Manifold >> Downpipe XTC Downpipe (optional cat, 2.5" or 3") ZZP Downpipe (optional cat, 2.5" or 3") Stock LSJ Downpipe w/ cat (requires some modification for the Auto Trans.) Clear Image Automotive Downpipe (optional cat) >> JBP Vortex 3" Downpipe >> CTI 3" downpipe (optional cat) >> Catback GM Performance Parts (Performance/Touring) Videoclip Corsa (Sport/Touring) Videoclip Magnaflow (either 2.25" or 2.5") Videoclip Megan Racing PIC SLP Loudmouth II Videoclip SLP Loudmouth II Dual Outlet Videoclip JBP Vortex 3.0" >> Pacesetter Videoclip Ark Racing N2 (not produced anymore) Videoclip Ark Racing DT-S Videoclip Ark Racing GRIP Videoclip Tusdo N1 >> Videoclip Borla Videoclip Hahn Racecraft 3" >> Videoclip Clear Image Automotive (either 2.5" or 3") >> Stainless Works >> CTI 3" Videoclip ZZP 3" >> Custom piping >> Engine: (requires tuning) Forced Induction LSJ Supercharger Kit swap Hahn Turbo Kit ZZ Performance Turbo Kit ZZ performance Supercharger Kit Speed Mafia Procharger Kit (currently only available for Ion) PIC Custom turbo kit Camshaft JBP Tri flow camshaft >> Custom regrind Nitrous NOS Nitrous Express Zex Holly Vemon DynoTune Throttle Body Throttle Body port/swap Individual Throttle Body kits ZZ Performance Throttlebody adapter plate >> Injectors LSJ Injectors, or Stage 2 Injectors #33 Injectors >> #39 Injectors >> Siemens #60 Injectors >> Cobalt-Addiction #80 Injectors Cylinder Heads JBP Cylinder Head Kits >> Custom port and polish Pistons Wiseco Connecting Rods Flatlander Racing Pauter CARRILLO H-Beam >> CARRILLO Super A-Beam >> Electrical Jet Performance Chip MAF sensor Crate Engines JBP LE5 Performance crate engines >> Pulley Crank MRZ Performance >> (either smaller or OEM size) MD Pulleys JBP >> Z-spec Cobalt-Addiction >> Alternator MRZ Performance >> MD Pulleys Transmission: Manual Short Throw Shift kits TWM Short Shift Kit B&M Short Throw Shifter Ark Performance Any STS kit for the Getrag Transmission in some 2.4L and all Ecotec equipped Cavaliers will fit the 2.4L manual transmission (Some may require slight modification to fit properly) Clutch Kits Exedy Racing SPEC Competition Clutch Flywheels Fidanza SPEC ACT LSD (Limited Slip Differential) Quaife Miscellaneous ZZP master cylinder clutch rod >> N2MB Racing WOT Box Automatic B&M Shift Plus (for late 06+, wiring is a bit different) Transmission Tune LSD (Limited Slip Differential) Quaife Tuning: Our stock engine tune is rather conservative. Tuning parameters like power enrichment delay, air to fuel ratio, and spark timing will result in decent horsepower gains. Tuning after installing bolt ons (intake and exhaust) will further bring out the potentials of those modifications Tuning Equipment Hptuners >> (doesn't support 2008 ECM yet) EFI Live >> (doesn't support 2008 ECM yet) LS2-Edit >> Trifecta Performance Tuning AEM F/IC >> Canned Tune Vector Motorsport >> Jet Performance Chip Westers >> Legend: >>= link to product VideoClip= Video PIC= Picture If you see something missing just post it up and I'll add it. Also if you have a video clip or picture of your exhaust that isn't already up please post the link and I'll add it.