Hi, new to the board so Gidday.Im from New Zealand and have been on the hunt for some st4 headers for my s4. Are there many for sale in the UK and how much for a second hand set. My other queston is are the cylinder pipes the same size on the s4 as the st4 then change to 45mm after the 2 into one setup. So what im tring to say is if I take a s4 exaust and chop after the 2 into one set up and increase the pipe size that way?