....
Sound is very, very subjective and we each hear slightly differing ranges of sound anyway - My hearing might be better on bass than yours and yours might be better for treble etc etc.
Of the main performance exhausts: Milltek, APR, Blueflame - They all deliver similar performance AFAIK but they each have slightly different sound characters.
Today we swopped to a smaller 'Resonator' section on my Milltek - There is hardly anything in my shallow backbox and so a resonator is needed to stay legal. It's now much more 'burbly' and pops more on shifts as well as sounding stronger. It hasn't killed the Grrrrrrrrrrrr!! from my engine mounts I'm glad to say.
I can't praise my black satin ceramic tips enough - So eeeeeasy to keep clean and never hot to touch.
I don't know yet what Milltek will decide - My system is somewhat custom but could be offered to others - It's up to them.