All the information has been out there since ~06. There have been several threads on this subject here and on toymods. In saying that the search function here is not as good as on other forums and you have to sift through a bunch of threads to find the ones you're looking for.

To answer your question, in short, it will bolt in, only thing that needs mods is neck. I used shortened KE70 necks both times I've done it and used the rubber joiner to connect to AE86 tank. Yeah, you lose the breather thing but I never had problems with the neck filling up and killing flow at the bowser.