"The BW S366 twinscroll" there are quite a few variants, you should look into part numbers and compressor maps to make sure you know what you are looking at//to be expecting when you actually purchase a unit.
As for manifold and IC, you have gleaseman, you have turblown, you have various other manufacturers/vendors here (a-spec etc...), all make QUALITY products, even some people make good numbers with ebay manifolds, hell cast manifolds are solid if you can make it fit (I'm sure it's doable depending on comp. housing size).
As for IC anything but a top mount lol, I plan to go a2w just because least pressure drop and a few other nit-picky reasons. You can look for 'kits' or you can size it up and fab/spec out a few components and purchase accordingly. You pay a bit of a 'premium' or 'markup' on any type of kit. That being said - a lot of the time, it can really be worth it.