Okay, here's the English text compared (just did a crude comparison with some modernized KJV). Due to the sheer amount of time it takes to paste in the Greek, that will be done separately. Consider this just to get the general idea of what's being changed.
Matthew 19:16 And, behold, one came and said to him, Good Master, what good thing will I do, that I may have eternal life?
Luke 18:18 And a certain ruler asked him, saying, Good Master, what will I do to inherit eternal life?
Mark 10:17 And when he was gone forth into the way, there came one running, and kneeled to him, and asked him, Good Master, what will I do that I may inherit eternal life?
Matthew 19:17 And he said to him: Why do you call me good? there is none good but one, that is, God: but if you will enter into life, keep the commandments.
Luke 18:19 And Jesus said to him: Why do you call me good? none is good, except one, that is, God.
Mark 10:18 And Jesus said to him: Why do you call me good? there is none good but one, that is, God.
Matthew 19:18-19 He said to Him: Which? Jesus said: you will do no murder, you will not commit adultery, you will not steal, you will not bear false witness, Honour your father and your mother: and, you will love your neighbour as yourself.
Luke 18:20 you know the commandments, Do not commit adultery, Do not kill, Do not steal, Do not bear false witness, Honour your father and your mother.
Mark 10:19 you know the commandments, Do not commit adultery, Do not kill, Do not steal, Do not bear false witness, Defraud not, Honour your father and mother.
Matthew 19:20 The young man said to him, All these things have I kept from my youth up: what lack I yet?
Luke 18:21 And he said, All these have I kept from my youth up.
Mark 10:20 And he answered and said to him, Master, all these have I observed from my youth.
Matthew 19:21 Jesus said to him, If you will be perfect mature, go and sell that you have, and give to the poor, and you will have treasure in heaven: and come and follow me.
Luke 18:22 Now when Jesus heard these things, he said to him, yet lack you one thing: sell all that you have, and distribute to the poor, and you will have treasure in heaven: and come, follow me.
Mark 10:21 Then Jesus beholding him loved him, and said to him, One thing you lack: go your way, sell whatever you have, and give to the poor, and you will have treasure in heaven: and come, take up the cross, and follow me.
Matthew 19:22 But when the young man heard that saying, he went away sorrowful: for he had great possessions.
Luke 18:23 And when he heard this, he was very sorrowful: for he was very rich.
Mark 10:22 And he was sad at that saying, and went away grieved: for he had great possessions.
Matthew 19:23 Then said Jesus to his disciples, truly I say to you, That a rich man will hardly enter into the kingdom of heaven.
Luke 18:24 And when Jesus saw that he was very sorrowful, he said, How hardly will they that have riches enter into the kingdom of God!
Mark 10:23 And Jesus looked round about, and said to his disciples, How hardly will they that have riches enter into the kingdom of God!
Mark 10:24 And the disciples were astonished at his words. But Jesus answered again, and said to them: sons, how hard is it for them that trust in riches to enter into the kingdom of God!
Matthew 19:24 And again I say to you, It is easier for a camel to go through the eye of a needle, than for a rich man to enter into the kingdom of God.
Luke 18:25 For it is easier for a camel to go through a needle's eye, than for a rich man to enter into the kingdom of God.
Mark 10:25 It is easier for a camel to go through the eye of a needle, than for a rich man to enter into the kingdom of God.
Matthew 19:25 When his disciples heard it, they were exceedingly amazed, saying, Who then can be saved?
Luke 18:26 And they that heard it said, Who then can be saved?
Mark 10:26 And they were astonished out of measure, saying among themselves, Who then can be saved?
Matthew 19:26 But Jesus beheld them, and said to them, With men this is impossible; but with God all things are possible.
Luke 18:27 And he said, The things which are impossible with men are possible with God.
Mark 10:27 And Jesus looking upon them said, With men it is impossible, but not with God: for with God all things are possible.
Matthew 19:27 Then answered Peter and said to him, Behold, we have forsaken all, and followed thee; what will we have therefore?
Luke 18:28 Then Peter said, Lo, we have left all, and followed thee.
Mark 10:28 Then Peter began to say to him, Lo, we have left all, and have followed thee.
Matthew 19:28 And Jesus said to them, truly I say to you, That you which have followed me, in the regeneration when the Son of man will sit in the throne of his glory, ye also will sit upon twelve thrones, judging the twelve tribes of Israel.
Luke 18:29 And he said to them, truly I say to you, There is no man that hath left house, or parents, or brethren, or wife, or children, for the kingdom of God's sake,
Mark 10:29 And Jesus answered and said, truly I say to you, There is no man that hath left house, or brethren, or sisters, or father, or mother, or wife, or children, or lands, for my sake, and the gospel's,
Matthew 19:29 And every one that hath forsaken houses, or brethren, or sisters, or father, or mother, or wife, or children, or lands, for my name's sake, will receive an hundredfold, and will inherit everlasting life.
Luke 18:30 Who will not receive manifold more in this present time, and in the world to come life everlasting.
Mark 10:30 But he will receive an hundredfold now in this time, houses, and brethren, and sisters, and mothers, and children, and lands, with persecutions; and in the world to come eternal life.
Matthew 19:30 But many that are first will be last; and the last will be first.
Mark 10:31 But many that are first will be last; and the last first.
I highlighted some of the major differences.
#1 the ruler states 'have' in Matthew versus 'inherit' eternal life in Luke and Mark.
#2 Luke reveals that the the individual coming to Christ was a ruler (which explains his wealth); and this is no coincidence since Luke would be adding to the kingship extension.
#3 Matthew extends Christ's response in verse 17 with "but if you wil enter into LIFE keep the commandments", whereas Luke and Mark omit this bit
#4 the order of the commandments Christ states have a different ordering: not sure (yet) what the ordering changes mean, this will have to be analyzed separately.
#5 Mark changes Christ's response and adds that he 'loved' the ruler (a derivative of agape is used, so it's definitely loved), whereas Matthew and Luke omit this.
#6 Mark 10:24 is added where Christ repeats himself (this "repeat" is omitted from Matthew and Luke).
#7 In Mark 10:26 the context of the disciples talking about it among themselves is given whereas this is omitted in Matthew and Luke
#8 Mark 10:21 adds the "take up the cross", whereas the other two omit it
#9 Matthew 19:29 specifically uses "inherit everlasting life" whereas Luke and Mark do not use this phrase, instead just eternal life.
#10 Luke omits "the first will be last / last first"
At this point it's clear to see how Luke is aiming more with the focus on the new change and the kingship / whereas Mark adds the finalizing touches and makes changes the other two do not.
Now there some parallels with the outer darkness passages (particularly the ending first last / last first). The fact that Luke omits it could be a clue-- since Luke is involved with the changeover, and Mark (which is the final update) adds it back in. I'll have to see if this the same across the board later.