Mine's refering to a very open gtr system,
i run the trust front pipes, Same as nismod pictured above..
but i've modified my veilside 3.5 inch exhaust, actually found it to be way too quiet so i cut out one of its large mufflers and it opened it up alot, yet its still very quiet considering what it has or more so hasn't.
before with the full veilside system it was very very quiet..