I had a 4/4 and the silencer got rust holes not long after buying ( secondhand from dealer)
They sent a replacement...stainless straight through but standard dimensions, from the MMC factory.
The interior was a straight pipe with perforations to the outer section and no baffles.
Sound improved nicely.
I think performance perked up too....or did the new noise create that impression!
I have read in a few places of people using a bar to "modify" internal baffles.
Some even claimed to have done similar to catalysts but no mention of effect on emissions in next MOT!
