You have to state if you want a resonator or not, I think they are not much, ask a price for a resonator they'll be able to tell you on the spot and just add it onto the total price.

They will quote you to make the catback including;

flanges, hangers, rubber mounts if they are worn, muffler placement and tip fitment

Do 2", anything bigger will be loud and piss you off, it doesn't sound like you care if you have 1kw more in the upper power band for double the noise