Have you got a big bore exhaust?

[Prepper1]

£1 from the pound shop for a box of brillos.
You can however replace them with either the copper ones or the stainless steel.

Length of back box life not a major concern if you change/ inspect on a monthly basis as I plan too.
But seeing how your exhaust traps water along all its length, a little bit more wont make any difference for me anyway.

I personally don't have the £30 quid free right now so... nor do I intend spending more on it than necessary, I've gone down that route with cars before, blow loads of wodge on them and the missus either writes it off or it gets nicked or fails the mot terminally. That is unless you want to send me a new back box... citroen xsara 1.4i v reg... some of us arent as well off as you seem to be...we have to manage by the skin of our teeth...