Hi Greg, just checked under the bonnet. It's the small silver compressor. Thanks for your help so far. do I need to do anything to the brakes and/or suspension since it's a heavier engine? or is all that standard across the board? Was thinking about a large alternator since I'm running sound system, lighting and my headlights are now more powerful too. It'd have a standard 55amp, not sure how much higher to go.