I really hope Piggyback Authorized Collection releases the official guide for this installment too. I still have my Piggyback official guides for GT3 and GT4 with protective sleeves as collector's items. I always loved them, because of the circuit maps (turns with their numbers and names), comprehensive setup guides (reading about the Limited Slip Differential suggestions at its setup and so on), etc. As a kid, when I had the GT3 one, I was really amazed with its content. Quite useful to be honest, because as many users noted before for GT it's not about how to do the things, it's reference material.
I do know Prima and Bradygames are like the publishers for guides on NA market, but some of those are not always official guides. Being an owner of many Bradygames imported guides and many Piggyback guides as well, I can say the Piggyback are miles ahead on exhaustive data and quality. I really hope they release the official one for GT5. If not, I guess I'll go with the one by Prima.
On their web site I do not see anything related to GT5 yet. I think I've sent them an e-mail to ask. If the answer is no, I'll start doing the pre-order of the Prima one this time. An official one like the one Piggyback did for FF XIII with a hard cover limited edition (numbered) would be brilliant.