I bet nobody could tell the difference between X5 and X7 in the dark...similarly between Deore and XT.
I'll go along with that. I upgraded from Deore to XT, because I thought they looked prettier, but if I'm honest, no real difference in shifting performance whatsoever.
The only thing to check is that the Shimano front mech will work with an SRAM shifter, I know some SRAM shifters aren't compatible with Shimano mechs and vice versa, but can't remember which ones.
As far as I'm awre front mechs are fine because they all work on the same pull ratio, it's just the rear mech. SRAM use a 1:1 ratio, not sure what Shimano use.
What year X5 stuff is it? The latest stuff is exactly the same as my X9 stuff from 2005 so it should work pretty well. My old X9 mech is a bit baggy these days, but it still keeps on working even after being on loads of bikes, including my DH bikes.
2015 Stanton Ti Switchback
2006 Specialized Demo 8
2013 Specialized Allez Sport
1999 Santa Cruz Chameleon
1994 Cannnondale Beast of the East (rebuild still in progress)