Why not a thread where we can share how certain exhaust systems sound?
Try to keep this thread informative, i.e. not just random Youtube clips but rather clips with info about the type of system or design of the system. This way we might find a nice design for our custom builds easier.

That being said I'll start off with a clip I shot tonight of a friends 75 3.0. Stock engine setup but the exhaust is completely without mufflers/silencers, cat only...
This clip doesn't do the sound justice at all, shot it with my Ixus 120 and it adjusts the volume automagically. We plan to hit some tunnels tomorrow though and I'll bring the proper camera.

The system is pretty much stock dimensions but w/o mufflers, double 2" from cat to gearbox cross member and 60mm (?) over the driveshaft into two beautifully finished 2" end pipes.

http://www.youtube.com/watch?v=2MIH2AtMQuE

This is the sound from inside the car. 3.2 24v. 42mm manifolds into 2 x 50mm down pipes converging into 63mm by gearlever into first box. Then 63mm to rear large box and 74mm last piece. Great sound out side.
Quick drive up my road.
http://www.youtube.com/watch?v=vMUs_VKEVu8

Good Idea Mats.

I have the inexpensive vic autosport muffler and straight through pipes from cast iron headers to the muffler. It sounds great. not too loud, not too soft..and has that slightly brassy italian exhaust note.

reasonable sound level with rear seats and carpet all out of car.

will post vid asap.

Here is mine:
Unknown cams, CSC-headers, straight mid-section and a burned out ANSA-muffler.

Outside:
http://www.youtube.com/watch?v=DYTKTO2Zkv4

Inside:
http://www.youtube.com/watch?v=A-h_RLOEpf0

Volume is very loud, but screams very nice and high pitched.