Was also thinking about sound quality, if people are saying the stainless ones for VF aren't sounding as good as mild-steel ones, that would mean the thicker-wall exhausts are sounding better? So making it considerably thinner than stainless again might not help sound-quality at all!
I also suspect the sound of otherwise identical exhausts are influenced by the tube wall thickness.
From what I gather, the thicker the tube wall the more energy is required for the tube to resonate and the resonance seems deeper which influences the base sound of the exhaust. Thicker tube walls = deeper resonance = deeper sound (all other things being equal).
As stainless exhausts seem to have thinner tube walls than steel exhausts, and I’d think titanium would be even thinner walled tubing than stainless (due to it being strong and light allowing yne thinner walls). Like for like, titanium exhausts would have an even tinnier sound.
However, the base sound an exhaust produces is dependant on header and exhaust design (tube diameter, how and where it tubes merges or changes volume as well as the muffler can volumes, baffles and their placement). And as titanium is rather light in comparison to thin stainless, let alone thick aluminised steel, they could build a much more complex shaped and sized exhaust to overcome any tinny sound titanium would naturally want to produce.
But I suspect packaging and cost focus is probably the biggest limitation in design as modern engine bays just don’t have the same space available as old school engine bays, especially for headers where cats tend to be placed closer and closer to the exhausts port to aid fire-up (I think they call it).
At the end of the day it all comes down to design and with after market, bling bling is an easy design aim which seems to sell so on that front stainless rules...
Wind instrument musical experts talk of tube wall thickness and how it influences the tone/texture/colour* of the base sound and of the effort required to play the instrument.... and only car manufacturers that produce squillion dollar cars contract musical instrument designers during the design of the intake and exhaust systems. Toyota LFA design is one example, see 27.30 below (where they talk about the intake sound, pity they don’t talk of the exhaust sound)
For the rest of us living in affordable land, bling bling will just have to do (though I must say Holden did a nice job design the MSE and bi-modal muffler with Bailey Tip)
* People who are into high end musical wind instruments and have an ear for the sound use these and more terms to describe the sound of the instruments but me, I’m anything but musical
