I think that whatever grounds corporations (and their customers) have to challenge these requests that those grounds have far more basis in the law than "it would be bad for business." If the grounds for challenge are baseless then a court will toss the case, but I think that would be highly unlikely.

People have a constitutional right to be secure in their papers and effects and the court should be the one judging where these rights start and end, and not the FBI.

Exactly what is so important that a warrant cannot be obtained from a judge before tapping these lines? Where is the justification that this is necessary to secure our happiness and freedom?

If it is necessary to repeal parts of the constitution then we should have a frank, open and honest discussion about it. The more likely case is that Augustus has no clothes.