Hello. I can't help you with your question regarding bore size, but I am going through the same thought processes as you are regarding sports cats and x pipe/centre section. The likes of Larini do sell sports cats and x pipes for the 3200, but If I'm honest I am put off by the price. I understand that a lot of thought and development work goes into these products, but I personally cannot justify that level of expenditure, just for more noise and a few extra horses. I have a pair of rear straight-through exhaust boxes on my 3200 that I have been using for the past year or so for the extra noise. They were made by Powerflow, so not the best quality in the world (just my opinion), however, they do sound rather good, and not at all tractor-like. My aim is to replace those with the stainless steel "sports" boxes I previously had (supplied by Autoshield), and to then get sports cats and x pipe made up. I have found somebody who I am hoping will be able to help, and am hoping to get my car across to him next week. I will happily report back if you or anyone else is interested. If that is a no-go, then my thought is to simply get an ECU remap. Although this would not increase noise levels, it would for sure release more power. Better still, and if funds permit, I might get all the exhaust mods done, and then also do a remap as well. My plans (funds and timing) depend on getting my leaking radiator fixed first.
