There's no point. Cars in this segment used to be great. Now they're all the same. Rolling, soulless computers. The only difference between them all is price and how fast the speedometer moves. You can't feel the difference, because they're so big and heavy.
The M5 died with the E39. The E60, which came out as flappy paddle only (until they later came out with a 6MT that had a traction control you couldn't turn off) signaled the end of the proper M5s.
The CTS-V is probably the spiritual successor to the E39 M5. I don't know what this is.