What is perfect virtue?

A link possible to Perfect virtue and about the fruits of walking a perfect way for maintaining it.

[Ananda:] "What, O Venerable One, is the reward and blessing of wholesome morality?"

[The Buddha:] "Freedom from remorse, Ananda."

"And of freedom from remorse?"...

Sīlena sugatiṃ yanti. Sīlena bhoga-sampadā. Sīlena nibbutiṃ yanti. Tasmā sīlaṃ visodhaye.

Here's an article which might answer exactly that.

A Treatise on the Paramis

The article is detailed. One paragraph from its introduction is as follows,

The "requisites of enlightenment" are the paaramiis themselves, the main topic of the treatise. The word paaramii derives from parama, "supreme," and thus suggests the eminence of the qualities which must be fulfilled by a bodhisattva in the long course of his spiritual development. But the cognate paaramitaa, the word preferred by the Mahaayaana texts and also used by Paali writers, is sometimes explained as paaram + ita, "gone to the beyond," thereby indicating the transcendental direction of these qualities. The list of paaramiis in the Paali tradition differs somewhat from the more familiar list given in Sanskrit works, which probably antedates the Mahaayaana and provided a ready set of categories for its use. Our author shows that the two lists can be correlated in section xii, and the coincidence of a number of items points to a central core already forming before the two traditions went their separate ways. The six paaramiis of the Sanskrit heritage are: giving, virtue, patience, energy, meditation, and wisdom. Later Mahaayaana texts add four more — resolution, skillful means, power, and knowledge — in order to co-ordinate on a one-to-one basis the list of perfections with the account of the ten stages of the bodhisattva's ascent to Buddhahood. The Paali works, including those composed before the rise of Mahaayaana, give a different though partly overlapping list of ten: giving, virtue, renunciation, wisdom, energy, patience, truthfulness, determination, loving-kindness, and equanimity. Unlike the Mahaayaana, the Theravaada never developed a theory of stages, though such may be implicit in the grading of the paaramiis into three degrees as basic, intermediate, and ultimate (section xi).

And from its conclusion,

(xvi) What is their fruit?

Their fruit is, in brief, the state of perfect Buddhahood. In detail, it is the acquisition of the form-body (ruupakaaya) resplendent with the multitude of meritorious qualities such as the thirty-two characteristics of a Great Man, the eighty minor marks of physical beauty, the fathom-wide aura, etc.; and, founded upon this, the glorious Dhamma-body (dhammakaaya) radiant with its collection of infinite and boundless meritorious qualities — the ten powers, the four grounds of self-confidence, the six kinds of knowledge not held in common with others, the eighteen unique Buddha-qualities, and so forth.[34] And so numerous are the Buddha-qualities that even a perfectly enlightened Buddha could not finish describing them, even after many aeons. This is their fruit.

And it is said:

If a Buddha were to speak in praise of a Buddha,
Speaking nothing else for an aeon's length,
Sooner would the long-standing aeon reach its end,
But the praise of the Tathaagata would not reach its end.

Other paragraphs, in the middle of the article, are more interesting (more practical, "petaining to practice"). They include:

(i) What are the paaramiis?
(ii) In what sense are they called "paaramiis"?
(iii) How many are there?
(iv) What is their sequence?
(v) What are their characteristics, functions, manifestations, and proximate causes?
(vi) What is their condition?
(vii) What is their defilement (sa"nkilesa)?
(viii) What is their cleansing (vodaana)?
(ix) What are their opposites (pa.tipakkha)?
(x) How are they to be practiced?
(xi) How are they analyzed (ko vibhaago)?
(xii) How are they synthesized (ko sa"ngaho)?
(xiii) By what means are they accomplished?
(xiv) How much time is required to accomplish them?
(xv) What benefits do they bring?
(xvi) What is their fruit?

Perfect virtue would be Arahantship. At a certain point it will be seen that behaviors not encompassed by ordinary definitions of ethical behavior will still result in suffering for one's self and others and that there is no real 'out' outside of being outside of existence, i.e., arahantship.

Meanwhile down here, every advance in ethical behavior (as derived from a basis in the Four Truths -- every 'point of view' will produce a different set of values and those values are the basis of what is called ethical behavior, so there is no one standard) brings release from future guilt and blame and that is no little reward.