Not forbidden to the guild members though right?
Nope - nobody, not even the guild, were allowed computers. Hence the reason for the existence of the guild - the prescience granted to them by the spice enabled them to safely traverse hyperspace.
i read the book, and i'm pretty sure the navigators in the book were visibly human and didn't live in a tank. their most distinguishing feature was eyes so dark blue they were nearly black.
the tank is one of david lynch inventions, along with heartplugs and the fat baron's disgusting skin diseases. is it so much to ask to make the baron simply fat without this cartoonesque villian quality where he has to have MULTIPLE things grotesquely wrong with him?
Dune is about subtlety. not this ridiculousness.
Guild agents were normal humans, but navigators never appeared in the original book. Their first appearance was the second Dune book - Edric does indeed live in a tank, and is deformed.
He should have never written a sequel. Dune is probably the best single book I have ever read. Even the next two sequels were nowhere near as good. I think I've read the first Dune book about 5 times now, and every time I read it, I'm amazed at how detailed the world is, and how interesting the characters are.
Frank Herbert's own Dune sequels were comparatively not great, but his son's were downright terrible. I remember reading the first few pages of one and putting it down, I just couldnt do it.