Here was an interesting exchange by Jimmy Akin and Scott Windsor on how to deal with Calvinists that swim the Tiber.
Jimmy Akin proposes Calvinists converting to Rome can keep "TULIP" if they understand it this way:
A Thomistic TULIP
In view of this all, we might propose a Thomist version of TULIP
T = Total inability (to please God without special grace)
U = Unconditional election
L = Limited intent (for the atonement's efficacy)
I = Intrinsically efficacious grace (for salvation)
P = Perseverance of the elect (until the end of life).
There are other ways to construct a Thomist version of TULIP, of course, but the fact there is even one way demonstrates that a Calvinist would not have to repudiate his understanding of predestination and grace to become Catholic. He simply would have to do greater justice to the teaching of Scripture and would have to refine his understanding of perseverance.
Scott Windsor's approach:
That is well and good, but the criticism of using their terminology still exists (as with my initial article which did much the same as Akin's here does). If one is to convert to the True Church, then why hang on to errors of the past at all? When one converts, they need to RENOUNCE their past - and EMBRACE that which they now KNOW to be the Truth. Let's not "tiptoe through TULIP," let's just crush the TULIP so they can move on and know the Truth.
Hmm... let's see...which one is the correct approach?