My throttle cable broke on my integra. I'm looking to replace it but need need info on which one I should get. I have a 2001 GSR with a b20v/b16 head. Should I get a GSR throttle cable or a b16 cable? Is there a difference between the 2?

ITR/LS/B16 they all use the same style manifold vs the snail of the c1. So Si one just go onto majestic and look at the P/N

Depends on what throtle body your using! you could have a gsr throttle body/bracket on a b16 intake manifold or vise versa, what throtle body/throtle cable bracket are you using?

I have a Victor X manifold with a 70mm tb but not exactly sure what brand!

that's a normal ls/Si/ITR style cable+bracket, I have never heard of anyone using that awkward gsr bracket on a non gsr manifold.. Heck even skunk2 tells you, you need to swap over to an ls/itr style cable when using their manifold up from a gsr one.