Why does the Torah write "Im Kofer Yushas ALa'av"?
Rashi: This is one of three cases where "Im" is not conditional. 1
Ramban: Because, since Kofer is a Kaparah (like Korbanos), should he opt not to go to Beis-Din, they will not obligate him to pay. 2
Seforno: Because he is only Chayav to pay Kofer in the event that witnesses testify that the Mu'ad gored.
Targum Onkelos and Targum Yonasan: Following on from the previous Pasuk, the Torah is simply stating that, in the event that Beis-Din obligate him to pay Kofer, then he pays and is Patur from Misah.
Bava Kama, 43b: To include where the ox intended to gore an animal, but it inadvertently gored a human-being, in the Din of Kofer. 3
Oznayim la'Torah: Refer to 21:22:156:2.
Ramban: Even if he does go to Beis-Din, and Beis-Din obligate him to pay, they will not coerce him to pay by taking a security until he pays (as they do in the case of someone who is Chayav a Chatas). Targum Yonasan however, refers to the payment as a K'nas (a fine), in which case it seems that Beis-Din will force him to pay.
Even though the ox is not stoned (Torah Temimah).
If an Shor Mu'ad belonging to two partners gored another ox with two hundred Zuz, how much must each partner pay?
Bava Kama, 40a: Each partner must pay two hundred Zuz. 1
Since Kofer = Kaparah, and there is no such thing as half a Kaparah.
The value of whose "Soul" must he pay?
Rashi: This is a Machlokes Tana'im in the Mechilta: According to R. Yishmael
Which we learn from a Gezeirah Shavah "Alav" "Alav" from Ka'asher Yushas Alav Ba'al ha'Ishah"
What are the implications of the word "ke'Chol asher Yushas Alav"?