What I know about T-cases is secondary to what I know about posting clearly. When you delete something, mentioning whether you replaced it with something else can be useful. Just sayin'.

 

rear lsd(USDM) with rearranged plates vs rear ayc(JDM, EDM) - very similar.
ayc much comfortable in dd.
lsd stronger, not so comfortable.

removing ACD make sense only for DRAG car. read: non-acd=subaru
don't break an EVO, buy subaru if you want remove all systems)))

 

I had my ACD system removed when I started hearing the whine of death (transfer case gear whine). I had my whole drivetrain reworked by Jon at TRE and had the transfer case internals swapped to an older LSD T-case and had the max-lock rear diff upgrade performed. Keeping in mind that this is MORE expensive than replacing the ACD pump, I am now rid of the pump and it's potential failures, the extra weight over the front end, and I still get plenty of 4wd grip from the upgrades. I track the car at regional HPDE's, but no auto-x (I hear that's where the ACD and AYC really shine) so I don't miss it at all. If you're in your Evo for the long haul and don't plan on selling it later on, going this route can be worth it.