I replaced the central muffler on my TD5 130 with a straight through pipe today. The replacement section fits up to the same flanges as the original LR one so I can just put the original back easily.

It's hardly noisier at all, just a bit throatier. The main sound difference is that you can clearly hear the turbo whistle at the back now.

Pick up at low revs seems better (under 2000RPM), so I guess the turbo is spinning up faster, but can't notice any difference at higher revs.

Has anyone got any empirical evidence (ie a dyno of before and after) as to the improvement with the straight through system?

Thanks
David