///MBan said:The headers definitely increased the volume and changed the tone, but I installed them at the same time as the s-pipe, so hard to say how much of a difference the s-pipe alone would make. I considered using the SS x-pipe with the standard rear mufflers but on balance I thought it would increase the things I didn't want (rasp and drone) in comparison to using the stock x-pipe and SS Powerloops. You've got the parts, so why not try them?
I picked up about 9% power by adding the V1 stepped headers but they took some modification to fit a right hand drive car. I'm not sure if you're RHD or LHD? Peak torque was pretty much unchanged but it made some good gains in other parts of the rev range. I made a thread about it:
viewtopic.php?t=128400
Thanks Mban!
I will use the cats + xpipe, but needed to choose between the race or loops.
Also interested in buying the headers stepped or non-stepped.
Thats why i asked

Im on a LHD car. im gonna check out your thread, thanks for the link!