To start lets make a goal. The goal is to figure out what causes the difference in sound to the Maserati Granturismo motor a 4.2 cross plane v8 with a higher pitched and more growl exhaust note.... vs ... The base C7 corvette v8 which is a 6.2 cross plane v8 which is has a harsh thumper Harley-esk sound. Summing up what I think I know thus far... Compression on the Mas GT is 11.25:1 and the C7 is 11.5:1. The firing order for the GT is 1-8-4-2-7-3-6-5 The firing order for the C7 is 1-8-7-2-6-5-4-3 Although, as far as I am aware, CR makes little difference, and from what I know firing order obviously can play a huge role here but I'm stuck with what I have on that part. They both use short tube headers, probably because of space constraints - factory. The GT uses a X-Pipe in the system, while the C7 does not. The C7 uses a valve system in the exhaust where the https://www.amazon.com/dp/B002ONU8A8. They both have the 4th order v8 sound, BUT the Maserati doesn't have the half order that sound gives the C7 the typical American thumping Harley-esk sound. The C7 has a 2 valve vs the GT which uses a 4 valve may make a difference. 2 valve systems have a bigger but softer blow down. A single exhaust valve gives a deeper lower frequency noise. More exhaust valves will give it a higher frequency. As far as internal component weight- the vibration won't translate into reverb into the pipes. Radiated shell noise is something else- you don't want that. You want to engineer the noise from exhaust orifice noise and perhaps intake orifice noise. As far as difference in dome and port shape and length, port and chamber won't make much difference- it may change the max rate of pressure rise of the cylinder and that leads to high freq combustion noise which you want to dampen out. Here is a picture of a vehicle semi anechoic chamber for future reference - if it is brought up in this topic. https://lotusproactive.files.wordpre...09_12_71pb.jpg In VW world, the 12v VR6 doesn't sound that different than 24v VR6 for example is mute because it's anecdotal unless you have back to back tests in a vehicle semi anechoic chamber with no other changes. VW would have made a host of changes from vr6 12 v vs 24. Honda hemispherical B series heads all sound the same, regardless of displacement. Haven't noticed much difference in changing compression ratio or stroke or bore on a 1.8T, although the VW 1.8T is turbocharged, turbos dampen out and change pulses from the exhaust orifice. The x pipe shouldn't act similar to what the cross over headers do in that they try to connect exhaust pulses for scavenging also causing the noise change. The reason they shouldn't make a difference is because almost all cross plane V8s have some form of cross over in the system for low speed torque reasons. For future reference for the Maserati Grandturismo S. Here the maserati sounds just like an American v8 truck harley-esk sound... go to 50 seconds in. VS larini aftermarket exhaust which makes it sound exotic go to 1:35 in. Here is the Corvette C7 6.2 This is what most of all the after market exhaust sounds like- which is basically a louder version of the factory exhaust go to 1:00 in. The corsa Exhaust sound is considered to be the most "exotic" esk sound the C7 has available currently Maybe equal length shorty headers, keep lengths symmetric to keep half orders down? Any thoughts on this?