Prolly like 5-7 or so. Saw one dyno where the kn fipk added like 7whp or so. Test pipe usually gives around 5 I think.

 

washing the car doesnt do much to clean off the buildup, a claybar works well

 

To get it off for me I used a chrome and metal polish and it took it off in seconds. Not sure if that stuff hurts the paint but did not appear to at all. If claybar works as well I'm sure that's a better option.

 

I'm not even worried about making power, this is purely for the aural experience


Claybar is a bit more work .. hmm.. the HKS tips seem to be sucked in kinda exiting before the bumper I wonder if that helps with less build up?? who knows.. either way I hope sound will be awesome

 

Sound is awesome. Especially with the test pipe. Check out the hks vs greddy tic dual thread in the modifications forum as well. I posted up 4 bids or so of drive bys with the hks test pipe and fipk.