Looking to buy a new backbox for my Seicento Sporting, it's an X reg. I spotted this one ebay, any thoughts?

Is it worth replacing the system as they do one of those as well.

http://cgi.ebay.co.uk/Seicento-Spor...ZWD1VQQ_trksidZp1638.m118.l1247QQcmdZViewItem

Yes well worth replacing the centre pipe while you are at it.

They mention the ENGINE TYPE 176b2 but I have no idea what this is on mine

dont worry it fits based on age given of your vehicle in your original post and the age range given in the advert