Got myself a bug sti recently and I'm pretty sure there's a small exhaust leak from the front somewhere car has full decatted miltek before I book it into a garage to inspect then fix,is there a usal place to look 1st..

 

Look for any visible signs of black around the gaskets or any slip joints you have, could also be a cracked exhaust if it is a milltec, or at least that's what it was on mine, it was cracked right around the turbo to downpipe flange on closer inspection

 

I'll whip the turbo heat sheild off and cheaper it out before I book it in. Thanks

 

check lamba plugs are in propery if they have plugs.

 

Same has happened to mine .. and a few others that I know