Hi all. I've just discovered the back box silencer has been perforated.How easy is it to replace bearing in mind it'll be done at the roadside/driveway. I've been toying with the idea of a new performance exhaust for a while but baulking at the price of a complete system( i'm an Aberdonian and tight with money)so what about a performance back box. Can anyone recommend a back box with a decent sound not one of the boy racer fraternity noisy screamers but a nice purposeful throaty sound. Cheers Dave the tight Aberdonian