What size pipe? how long are the runs? how many 90's?

Most hydros I see these days run 2" and some long runs with more than a few 90's.

2.5" or 3" oil line for the whole run makes a huge difference in noise. The cheap round hollow Otis tank unit mufflers works pretty good then add the MEI silencer and its as quiet as can be and won't leak down the road.