Actually I've read those 613 so called "laws" in their original (but translated to English) format. I know where they are from. Like I said earlier, they are "biblically based," but not actually biblical. They are from the Talmud, and are the later rabbi's interpretations of Torah.
Since you (correctly, I might add) brought up "Torah," have you ever looked past Strong's for the meaning of the term? Strong, while the work he oversaw borders on genius in its' organization, is limited and often wrong or incomplete in its definitions. He tended to follow the catholic (universal) model in his interpretations.
My Vine's/Unger/White dictionary defines torah as "law; direction; instruction." In fact, and this is born out in the V/U/W explanation, law is the lesser meaning; not even the original meaning as "The "instruction" given to Moses
became known as "
the law"
or "
the direction" ... ." As for its' purpose, "God had communicated "the law" that Israel might observe and live." This is in accordance with, and occurs several times in Torah:
Deuteronomy 30:20 loving the Lord your God, obeying his voice and holding fast to him,
for he is your life and length of days, that you may dwell in the land that the Lord swore to your fathers, to Abraham, to Isaac, and to Jacob, to give them.”
If Torah (the first 5 books of the Bible) were actually "law," it's a strange way to write it: stories of the history of God's people; examples of faith and failure, good and evil; and the language is covenantal, not legal. Covenants say "if you will do this, I will do this, bt if this then that." Laws just say "don't." Now it is true the term does contain some connotation of "law." And there are some commandments in Torah that should (if one is smart) be taken as "law." But nowhere near 613. Those rabbinical interpretations at times get 2 or three "laws" from the same fragment of a verse. It only "became" the "law" after the rabbis in the diaspora got control over Judaism.
Torah is God's instructions for us in holy living. Holy means "set apart," and obedience to His instructions is what sets us apart from the world. A better term for "law" is the Hebrew "hoq." Pronounced "hoke" it means "statute; prescription; rule; law; regulation." But a loving God gave us instructions, not just a list of "laws" by which to live and conduct our affairs. The later rabbis, fearing Judaism would fall apart in the diaspora gave the Jews 613 "laws" by which to control their lives from waking up to going to sleep. Along with those "laws" came many fences- extra laws to protect the laws, basically. Also came a lot more traditions and daily rituals. That's the difference: laws control people, instructions guide them. Laws remove free will, instructions protect it as a basic right granted by God.
As "laws" the catholic (universal) church and the church fathers could say they were meant only for the Jews to show us lucky Christians that no one can keep the law perfectly (and thus no Jews, who most hated with a passion could therefore be saved- like they or anyone can say who is or is not). But as instructions well, those just might apply to everyone. And that would have cramped the style of most of the early church leadership most severely! If meant only for "those unlucky Jews" and not for us then we can do as we please. And if you know history, they pretty much did just that!
One does not need to become rabbinically Jewish. As I said, contemporary Judaism is nothing like that of any 1st cen Judaism. And yes, there were several sects and some "Judaism's" that were really so different they could be called another Judaism in the 1st cen AD. You are probably familiar with one of these- the Samaritans. So if someone wants to become "Jewish," my first question would be "What kind?" However as a Christian, regardless of denomination, if you are "saved" then you are grafted onto the Hebrew rootstalk. I would therefore recommend at least a decent understanding of Torah, the 1st 5 books, also called the Pentateuch. God's instructions are timeless.