Hot water would be even better: remember, it has to evaporate. This will be easier if water is already close to boil, much easier than if it was close to freeze. No risk of water droplets in the manifold.
And this is not BS!
My butt-o-meter is really sensitive to noise: the louder the stronger.
This maybe explains because everyone is buying cat-back's thinking it will bring power.
I reinstalled the Stock exhaust 3 weeks ago and I'm happy! I had an extremely noisy Corsa: cool the 1st week but a real pain during long trips. I installed tar plates and a special noise dampening foam in the whole car and it was still too loud.
...headers are still there... they do make the difference