I just installed a K&N drop in filter and hotter Autollite APP5263 lugs,Anybody
got any other suggestions for easy performance? I new to the HHR's only had it for a week but I love it. I was suprised w/ the perfornce of the 2.4L

 

When I got my hhr I had a KN intake, Bad Mab header and ZZP catted downpipe. Was a lot of fun with that set up and sounded really nice. Car pulled noticeably faster with those bolt ons too.