Aluminized steel can be rewelded, though the specifics of what you'd specifically need are a bit beyond my expertise. I do know that the aluminization coating is only a single layer above what's basically galvanized steel. As for how long an aluminized system will last, it really depends on climate and application. Here in Phoenix where there's very little little rain (much less snow and road salt), Aluminized systems can last hundreds of thousands of miles without issue. Other places, aluminized kits can look worse for wear after a couple of years. If you have concerns at all, you'd probably be better off with a true 409 or 304 stainless steel kit.