No Catholic who knows their faith thinks that their salvation is "based on [their] decision and [their] good works". Can we please just put that canard to rest, or are you going to insist on telling me I'm a bad Catholic because I know full well that I am saved first, last, always, and only by the grace of God won on the hill of Calvary?
Rome does not acknowledge sanctification and justification as separate works of God in salvation. It makes human works the basis for justification which merit eternal life:
"Justification...is not the remission of sins merely, but also the sanctification and renewal of the inward man. If any one saith, that the good works of the one that is justified are in such manner the gifts of God, that they are not also the good merits of him that is justified, by the good works which he performs through the grace of God and the merit of Jesus Christ, whose living member he is, and does not truly merit increase in grace, eternal life, and the attainment of eternal life, if so be, that he depart in grace, and an increase in glory, let him be anathema"
(The Canons and Decrees of the Council of Trent. Found in Philip Schaff, The Creeds of Christendom (Grand Rapids: Baker, 1910), Decree on Justification, Chapter VII, Canons X, XXXII).
Ludwig Ott emphasizes this in these words:
"Justification is the declaration of the righteousness of the believer before the judgment seat of Christ...The Council of Trent teaches that for the justified eternal life is both a gift or grace promised by God and a reward for his own good works and merits... According to Holy Writ, eternal blessedness in heaven is the reward...for good works performed on this earth, and rewards and merit are correlative concepts"
(Ludwig Ott, Fundamentals of Catholic Dogma (Rockford: Tan, 1974), pp.254, 264).
John Hardon likewise confirms this point of view when he writes:
Habitual or sanctifying grace is a supernatural quality that dwells in the human soul, by which a person shares in the divine nature, becomes a temple of the Holy Spirit, a friend of God, his adopted child, and able to perform actions meriting eternal life
(John Hardon, The Question and Answer Catholic Catechism (Garden City: Image, 1981), Question #1074).
So Roman Catholic theology teaches that justification is obtained by receiving grace through baptism, and is maintained through the sacrament of penance, the mass and the works of sanctification which in turn merit eternal life. It is important to point out that sanctification in Roman Catholic theology is not only the righteous acts of individuals cooperating with the grace of God but participation in the sacraments of the Church. A state of sanctifying grace, by which a person is justified, cannot be maintained apart from the sacraments. Justification then is not by grace alone (in the biblical sense) or on account of Christ alone (in the biblical sense). Therefore it is not by faith alone (in the biblical sense). In fact, the Council of Trent condemned the teaching of justification by faith alone stating:
If anyone saith that by faith alone the impious is justified in such wise as to mean that nothing else is required to cooperate in order to obtaining the grace of Justification...let him be anathema...After this Catholic doctrine on justification which whosoever does not faithfully and firmly accept cannot be justified...(The Canons and Decrees of the Council of Trent. Found in Philip Schaff, The Creeds of Christendom (Grand Rapids: Baker, 1910), Decree on Justification, Chapter XVI, Canon IX). There's much more here... http://www.christiantruth.com/articles/RCJustification.html