While true, I'm not sure how Ford would view it if an engine issue arose. Also, wouldn't long tubes require a tune to see gains? This is what I consider the greatest threat to my warranty (unless Ford Performance decides to offer a tune that keeps the warranty intact).
If you don't mind...
I agree, I love the sound of those Kooks long tubes but am too worried about warranty to take the plunge.
My hope is that the Corsa x-pipe adds a bit of the 'wail' but is more 'composed' than a straight resonator delete.