Northwest Members - 05 m6

Is it normal for my car feeling slower after install of longtube headers? Is the air to fuel ratio causing that? Should i also change spark plugs?

Stock exhaust other than the new headers? It maybe flowing really well and then getting a little choked up in the stock exhaust. Check and make sure evrything is hooked up right. They may have forgot something at the shop. I've found MAF sensors and such unplugged in the past.

You need to get it tuned after longtubes!

ellis at speed secrets did the headers and I have full corsa exhaust. I think it just needs to be tuned.