Here's a tip which might save you a few quid. I've got a petrol Y reg, one of the silencers rusted into a hole (not too noisy but enough to fail MoT). I went to get it replaced and was told that the only replacement possible was the whole system, as it was fitted as a single part. Furthermore, it's a 'dealer part' (= Fiat prices) - £410 thank you! 
I considered my options (actually, I considered the depleted state of my bank account) and decided to do a bit of research; I found a local company which fitted a replacement system in stainless steel (from the catalyst - which is stainless anyway - right to the very back) for £340 inc VAT. The guy said I could have it 'as noisy or as quiet as I liked' - I chose quiet! All these boy racer's cars in the yard, and here's my Multipla. Not cheap, but it'lll never need replaced again, as I'm certain that my £410 exhaust would have been singing away like Pavarotti within the next 3-4 years.
I considered my options (actually, I considered the depleted state of my bank account) and decided to do a bit of research; I found a local company which fitted a replacement system in stainless steel (from the catalyst - which is stainless anyway - right to the very back) for £340 inc VAT. The guy said I could have it 'as noisy or as quiet as I liked' - I chose quiet! All these boy racer's cars in the yard, and here's my Multipla. Not cheap, but it'lll never need replaced again, as I'm certain that my £410 exhaust would have been singing away like Pavarotti within the next 3-4 years. 
