Tampering (Tahreef) in Quran
Well present day shias don't openly says that Quran has been tampered. But this is the taqiyah they are doing. If this is not the case, than why do they read those books of their scholars and why do they accept those idiots as their grand scholars who claim again and again in their books that Quran has been tampered? The thing is they are doing taqiyah (lying) and kitman (hiding) , an essential part of their faith, and we will expose this here very clearly insha'Allah.
Shia Tafasir (Commentaries) and Tahreef in Quran
Tafsir by Farman Ali
Translation: “If we take out this verse (of purification) from the middle, and then we read the verse (addressed to the wives) from the beginning to the end, we then find no fault in it and it looks better in this form. From this, it is clear that this verse (of purification) does not belong to this place and it was added deliberately for some special purpose.”
(source: Tafseer e Farman Ali, Commentary on Verse 33:33)
المستفاد من جميع هذه الأخبار وغيرها من الروايات من طريق أهل البيت عليهم السلام إن القرآن الذي بين أظهرنا ليس بتمامه كما انزل على محمد صلى الله عليه وآله وسلم بل منه ما هو خلاف ما أنز الله ومنه ما هو مغير ومحرف وإنه قد حذف عنه أشياء كثيرة منها اسم علي عليه السلام في كثير من المواضع ومنها غير ذلك وأنه ليس أيضا على الترتيب المرضي عند الله وعند رسوله صلى الله عليه وآله وسلم .
وبه قال علي بن إبراهيم
http://rafed.net/books/olom-quran/al-safi-01/03.html , ( Screen Shot )
'It is clear from all of these traditions and quotations from the Family of the Prophet (Sallallaahu Alayhi Wasallam) that the present Quran is not the complete Quran which was revealed to the Prophet (Sallallaahu Alayhi Wasallam). In fact, there are verses that contradict that which was revealed; verses that have been distorted and places where omissions have been made such as the names of Ali, the Family of Muhammad (Sallallaahu Alayhi Wasallam) and, on several occasions, there were the names of the hypocrites. Moreover, the present order of the Quran is not according to the preferred order of Allah and His Messenger. Ali ibn Ibrahim (a renowned commentator) also holds this opinion.' (Tafseer of Saafi: l:49)
Tabatabai says in his Tafseer Al Mizan about verse 33 of Sura 33 ( the famous verse of the Koran that Imami argue to prove their beliefs on the members of Ahl ul-Bayt)
فالآية لم تكن بحسب النزول جزء ا من آيات نساء النبي ولا متصلة بها و إنما وضعت بينها إما بأمر من النبي أو عند التأليف بعد الرحلة
Tafsir Al Mizan Volume 16 (online)
"The verse (purification) according to the revelation was not part of the verses of the Prophet's wives and had no connection (with verses) but it was added (between verses) or by the Prophet or after his death during compilation (the companions). "
Tafsir Anwar un Najaf
The author says the same thing about the verse 33:33, but adds it may have been done in error or deliberately. (Last two line)
By Maulana Sayyad Zafar Hasan
The author says about 33:33 that such inconsistency can't be found even in the speech of a good speaker, like we see in the verse 33:33. The Maulana then argues how can it be in the word of God? Then the Maulana goes on to say that its very clear that it has been deliberately done for some special purposes.
Moulvi Maqbool Hussain writes in his translation and tafseer of Quran (Chapter 12 "Yousaf") that Quran is corrupted by the caliphs but they are compelled under the order of their imam to accept this Quran how it is.
Shia Hadith Books
Shia's most authentic hadith book says the present Quran has 6666 verses while the Quran which ahlel bayt have with them has 17000 verses
Famous Shia Scholars and Tahreef in Quran
The most famous shia scholar , Mulla Baqir Majlisi, in his two most famous books , Bahaar-ul-Anwaar and Hayat-ul-Quloob believes in the tampering (tahreef) of Quran.
the guru of answering-ansar
The guru says , Quran is corrupt because there is no mentioning of Pakistan in it. He thinks the original Quran was an encyclopedia containing everything. Such are the gurus of the e-shia scholars.
Shaikh Mufeed says in his book
(Imam al-Baqir) said: When the Qai’m from the family of Muhammad, may Allah bless him and his family, arises, he will set up encampments and he will teach the people the Quran as it was revealed by Allah, the Mighty and the High. The greatest difficulty will be for those who have learnt it as it is today, because it differs from its original composition.
Book Title: Kitab al-Irshad (The Book of Guidance)
Author: ash-Shaykh al-Mufid
Publisher: Balagha Books in conjunction with The Muhammadi Trust 
Translated by: I.K.A. Howard
In another book, he says
All of what is between the two covers of the Quran is the Speech of Allah Ta’ala and His revelation; it does not contain any sayings of human beings, and it is most of what has been revealed, and the rest of what Allah Ta’ala has revealed as Quran is bestowed with (Al-Qaem) the Preserver of Shariah and Custodian of Rulings with none of it being omitted, even though the one who has compiled what is between the two covers as present today (Uthman) did not include this in the compilation due to reasons such as: his shortcomings in knowing some (of it), what he had doubts about, and some which he included and others he meant to exclude, while Amir al-Mu’mineen (Ali) compiled the revealed Quran from beginning to end, and collated it as it is supposed to be collated: so he put the Makki (verses) before Madani, and abrogated verses before those abrogating them, and put all of it as it is required to be put, and for this reason (Imam) Jafar ibn Muhammad as-Saddiq said: “By Allah if the Quran was read as it was revealed you would have found our names as those before us were named”…
Authentic Hadiths have passed from our Imams (A.S.) that they have ordered (us) to read what is between the two covers, and that we do not resort to any other, be it in addition or subtraction until the Qaem emerges and he would read to people the Quran as Allah Ta’ala revealed it and as collected by Amir al-Mu’mineen (Ali) and they forbade us from reading what is mentioned in Hadith of words that are in excess of what is established in the Mushaf because it did not come through Mutawatir (narrations), but through individual (narrations), and a person can commit mistakes in conveying it, and whenever a person reads what is contrary to what is in the two covers he will make himself prone to (the attacks) of those who differ with us (i.e. Sunnis), and to the mighty (Sunni rulers) and thus he would expose himself to perishing. Thus, they (A.S.) prevented us from reading the Quran contrary to what is mentioned between the two covers.
Book Title: Masa’il as-Sarawiyya
Author: ash-Shaykh al-Mufid
Publisher: Dar al-Mufid in Lebanon, Beirut 
Editor: Sa’ib `Abd al-Humayd
Al-Sahifa e Alaviya
In the name of Allah the Beneficent the Merciful.
O Allah! Curse the two idols of Quraish and their two magicinas, their two rebellious people, their two accusers and their two daughters. Rebuke them, they have consumed Your sustenance and have denied Your obligations, both have discarded Your commands, have rejected Your revelation, have disobeyed Your Prophet, hav destroyed Your religion, have distorted Your book, have made Your laws ineffective, have declared Your obligatory actions as incorrect, have disbelieved in Your signs, have oppressed Your friends, have loved Your enemies, have spread corruption among Your people, have made Your world occur loses.
AYATULLAH ON DISTORTION OF QURAN