sb3, manifold u can do it at machine shops...those machinist around your area, u jus thave to give him a sample on wat u need to make in order for him to make a mold.
jetting size depends on your car capacity, for a decent 1.5 u can use 36mm jets which is sufficient for town driving and occasionally for some drags.
webet tuner well, u gotta learn to tune it urself...thats why u are getting a weber..to tune yourself untill you are satisfied with the performance and economy. most americans using webers tune themself, and i tune myself also untill i am satisfied and u know wat ur engine wats.