I'm actually thinking of just buying a metre of 2.5" stainless pipe and making 4 tips out of it that will look just like the liberty TB STi tips
I'd cut back the original protrusions to allow the tips to fit over them tightly and use a 3 grub screws to hold them on.
much more simple than cut/ shut and extend, especially with the space constraints.
So I would have mufflers from a PROPER STi that look identical to the TB STi muff's with s/s quad tips for half the price of what people have paid for the TB STi muffs....
I might do similar with some mild-steel and the original 3" tips aswell to see what looks best.
using grub screws rather than weld ing ton the tips will also allow the tips themselves to be aligned/ twisted as needed