My previously slightly leaky exhaust system has deteriorated a bit faster than I expected and I now have an urgent need to change it before the MOT in early January.

I had previously been thinking about getting a stainless system fitted but the slight blow by the back box that I currently have has been getting on my nerves and I'm wondering if I can live with the extra noise.
I thought about getting a system from Eternal just to chuck on for now, but they only list Omega systems for 2.5 and 3.0 to 2001 - in common with most exhaust suppliers on the web, it seems. They categorically stated that they don't have a system that will fit my 3.2. Nowhere have I found parts for the 3.2 listed, in fact. The closest I have come is a 2.6 system.
I need both centre sections and a back box, and, given recent reports of the quality of main dealer systems that's not an option.
Does anyone know what the interchangability of the systems is? 2.6 / 3.2 clearly have different cat sections compared with the 2.5 / 3.0, but does this mean the centre sections are different? Presumably the 2.6 system will fit but with a single tail pipe from the back box? Will a pre-2001 back box fit a facelift? Even with a little "modification"?
Any supplier recommendations?
TIA,
Kevin