When I was running my last Caterham, a 260bhp CSR, I wrapped the manifold from new, and it was still wrapped perfectly well when I sold it 7 years later.
It is supposed to help speed the exhaust gasses, but it could contribute to a build up of heat in the cylinder heads, though as far as I know, mine was fine.
It's very much a matter of personal preference, I wouldn't expect it to do any damage.
BTW those stainless steel zip ties are available at many builders merchants for some reason, and for not a lot of money either. Failing that, I have used copper wire in the past.
