I have a 1.8 sri and have just derestricted the airbox and goin to put on a veccy intake so I am looking for a good cat back system. When i was servicing my car i heard a blow from the exhaust so thought may aswell get an exhaust when i get paid. im looking for a twin piped back box ive seen one on ebay http://cgi.ebay.co.uk/NEW-ASTRA-MK4-...item5632c5cceb its make is cybox. Does anyone noo if they are good and if not what brand should i go for ? And if so should i get the centre box with it for a sporty sound or will i get more bhp without it ? any help would be appreciated thanks.