One last header Question..., sorry Options

[Vibe]

Hi I am about to get the pacesetter 3s-fe header for the GT, I've read threads where people have done this mod but I can't seem togather all the info i am looking for, what exactly needs to be done to make it fit? I know the 2 sensors need to be spliced or a new hole drilled, and a falange needs to be made, is it the top or bottom falange? then it needs to be welded? Also does the header come with the downpipe usually? Sorry if this is noobish but I have a shop willing to put it on I just wanna make sure i know everything. Thanks.