to add my $0.02
aluminized steel piping will not rust unless acted on by something. either the hanger rusting or being scratched. Once that happens it's normal steel, and rust will take over quickly.

Also beware of companies selling full cat-back exhausts with stainless steel mufflers. Notice they didn't say that the piping was stainless....
Then again mine is stainless yet the pipes are corroding away under my hatch because it's not the same quality stainless as the muffler, which looks almost brand new.