You continue to cite personal opinion without reference or sources, and thus your objections lack substance.
Great examples of how imperfect translations become "standards" of truth.
I would like to add a couple.
(KJV) Mat 5:39 "But I say unto you that ye resist not evil." and (KJV) Mat 6:13 "And lead us not into temptation, but deliver us from evil."
In both of these cases, the word "evil" is used as a proper name and means the "evil one" or Satan. The importance of this could be a topic for another discussion, but I think everyone understands the world of difference between not resisting crime and not resisting a criminal, or being rescued from crime as opposed to being rescued from a particular criminal.
(KJV) Mat 6:12 "And forgive us our debts as we forgive our debtors."
The verb to forgive in this case is known as the "historical present" and would be better translated as forgave rather than the present tense to forgive. This has an important implication in understanding God's mercy being conditional on our responsibility to do unto others as we would others do unto us: that we may not ask for forgiveness unless we have forgiven others. This is not at all the message that comes from using a simple present as KJV does.
This is of course tied with the Orthodox/Roman Catholics understanding that we may not hold a grudge and ask God's forgiveness for our sins.
These small semantic points along with your examples Cronos, such as the very essential one in your first example (Mat 5:48) "become" (future tense) rather than "be" (present tense), completely defeat the naive Protestant notion that the Bible is so simple and easy to comprehend something even a child can understand.
It also illustrates how those who go through life trusting their own interpretation of the Scripture are making sure they never fully understand it.
Finally, this also shows that different versions of the Bible (redacted and re-edited by human hands and human minds) by necessity corrupt the original in meaning and content, even if not intentionally. One more reason not to all our trust in the Bible alone, as jo kus properly pointed out a few posts ago.
As for using the Bible that the Apostles and Christ used, yes, the Massoretic/TR are the preserved words that was eventually translated into the English of the 1611 AV.