If I am a betting man I would say that the centre silencer on your Breadvan is already a straight through item (a number of cars comes with 'cherry bomb' type silences up front (1.6 CVH Escorts are one example).
As for standard system being best I would not say it is that easy . I have seen (compared against control cars where their systems stayed the same) a 306 GTi-6 gain almost 10BHP from going from a pattern exhaust to a genuine item (at quite a cost) including the cat and rear 'box. I have also seen a Renault Clio 172 be quite loud with an 'OE Spec' exhaust made by Klarus yet go to being super silent (and much better fitting) with a genuine Renault item which the owner got lucky with via ebay (a New unused item from a dealer).
Put it this way, my 306 GTi-6 became quieter when I fitted a Jetex system onto it and removed the 'stock' system (which was falling to bits 2 years after it was fitted internally with the front not being the first area to go).
As for standard system being best I would not say it is that easy . I have seen (compared against control cars where their systems stayed the same) a 306 GTi-6 gain almost 10BHP from going from a pattern exhaust to a genuine item (at quite a cost) including the cat and rear 'box. I have also seen a Renault Clio 172 be quite loud with an 'OE Spec' exhaust made by Klarus yet go to being super silent (and much better fitting) with a genuine Renault item which the owner got lucky with via ebay (a New unused item from a dealer).
Put it this way, my 306 GTi-6 became quieter when I fitted a Jetex system onto it and removed the 'stock' system (which was falling to bits 2 years after it was fitted internally with the front not being the first area to go).