Shia view on the Quran's authenticity & answering to Ghefari's doubts

Naser Ben Ghefari is one of those Wahhabis' which compiled books to defame the Shia. One of these books is "the principles of Shia Twelver's". in this book he tries to invalidate the Shia view on authority of the Holy Quran. In this essay, his two questions will be answered: 1. if the Shia believe in Quran text on condition that their imams affirmed that of not? 2. Whether the Shia maintain that it is only their imams that understand the holy Quran of not? Answering the first claim, we must say that almost all of the Shia believe that Quran by itself is understandable. The meaning of the Quotation "we cannot understand the Quran unless through custodians is explaining the Quran by the prophet successors. Since in some cases it needs more explanation. With regard to the second claim of Ghefari, we must say that both Shia and Sunni confess that Shia imams were of the best religious authorities in Muslim world