Hi guys, gonna be refurbing my original downpipes in the next couple of weeks as they have started to go rusty. The thing is i know what to do and what paint to get as it has been covered many times before however i cant find anything to say how much paint is needed? is one can of 500ml spray paint enough or should i buy 2. The reason i ask is that it is a lot cheaper online and i dont want to buy 1 online then be stuck and have to go out and buy another more expensive one in a local shop. Thanks