I'm tired of constantly fighting about this issue so I'm just going to post what I *THINK* are the differences between our 2 traditions.
God predestines from eternity past the elect and the reprobate. All men are trapped in total depravity unable to commit any good act without the irresistible grace of God. By this irresistible grace the elect have faith alone in Christ alone and Christ's perfect active obedience and righteousness is imputed to their souls. The faithful then know they are God's elect and are eternally secure (unless they fall away and the show that they weren't eternally secure - this is what I don't understand) This is justification. THEN Sanctification is the process where their actual lives/souls become righteous and holy, they turn from sin and towards God. BUT this process is not what God considers when evaluating their holiness so that in the eyes of God the thief on the Cross and St. Paul are equally righteous. Nevertheless the believer does become holy and this intrinsic personal holiness will be perfected instantly at death when all sin is killed with the body and in the instant process of glorification when the soul reaches heaven. But again, this intrinsic holiness is not what matters in terms of salvation, only Christ's extrinsic righteousness.
God predestines the elect to receive the grace sufficient for salvation. They are (ordinarily) baptized and washed of their original sin and receive the supernatural virtues of faith, hope, and charity which works with the grace of baptism to make them holy. The elect are given grace which they cooperate with and become more just and holy. On the basis of their faith they are declared just by God and made just intrinsically by being in a state of grace and by receiving the sacraments they receive more grace. If and when they fall into wilful grave sin (mortal sin) or apostasy the grace at work in their souls making them both holy and just is killed, they are no longer in a state of grace. But this grace can sacramentally be regained through Confession/Reconcilliation. To die in a state of grace means that God will put the soul (if necessary) through purgatory where they will be perfected in holiness. This is justification and/or sanctification. On judgment day they will be judged righteous based on the intrinsic righteousness God has wrought within their souls.
REGARDING 1 CORINTHIANS 6:11
"...But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and in the Spirit of our God"
In the moment of new birth and justification there is in some sense a real sanctification that occurs in the believer.
Paul is here showing that being made holy and being made just are not two separated processes but the same indivisible process. So the verse is a useful prooftext to show not only the interchangabiity of the terms sanctification and justification, but also the way in which Catholic theology speaks of multiple justifications, or an increase of justification, or a regaining of justification.
There is a "distinction" between justification and sanctification but not a division.
This is a division not a distinction because you believe sanctification is a superfluous process. The thief on the cross was justified and barely - if at all- sanctified, and St. Paul was justified and extremely sanctified, and the Reformed Tradition would have us believe that God views them identically in terms of righteousness and holiness.
Now. If I screwed this up significantly on the Reformed or Catholic side, please let me know.