As far as silencers are concerned, the ones originally supplied by BMW have an appalling reputation for longevity. They rust from the inside out and rarely last more than a few years if the bike is used regularly in a temperate environement. The usual cure is stainless steel replacements. It is a well documented and accpted 'sensible mod'. So much so, that I would be knocking money off if I were buying a bike with OEM exhausts still fitted (very unlikely by this time where I live - we love our weather in the UK), as I ould be factoring in replacements. I ride my bikes when it rains.
Headers are another matter, both my bikes are still fitted with OEM headers - but niether are pretty to look at and they are both getting a bit 'thin' now.
Another tuppence worth
