[Closed] I spec matchmakers

Evening all

Hopefully someone may be able to help here. I'm doing a bike build and it's been a while since I did one. I'm going for XT group set. There is an I spec B option is it worth doing opposed to normal shifter and break? I am using xt disc breaks as well initially.

Does it make shifter break positioning better?
Can I swap to a different make break later down the line ? are any other breaks I spec compatible?
Is it worth it ?
Anyone got any experience with this any comments appreciated ?

Cheers

Tim