Your best price is to order them straight from Bassani (cheaper).
I have stock manifolds into Bassani offroad pipe into Bassani catback.
It give a little bit more backpressure and tones it down a hair (not much).
They are installed in your tip's and held in place with a set-screw.It's tight....I couldn't
get my set-screw to align up so,I soft-hammered them in (They ain't going nowhere).