Anyone else have the sparco evo seats in their evo's? I really don't want to run a harness so I'm seeing what you fellas did to get the seat belt to fit into the receptacle. The bolster of the seat is too high so i can't get the seat belt into the receptacle (super tight fit between seat and armrest. So only way to get the seat belt into the receptacle is remove the armrest). I was thinking to somehow raise the seat belt receptacle or put something between the seat and receptacle to push it out further so the seat belt will fit.

 

You may have to go a junkyard and find a seat belt latch that has a longer bracket that the Lancer. I assume any seat belt latch will work for majority of the cars..but would start looking at other Mitsus that would have a longer bracket compared to the Lancer.

You probably need something like this:

 

As far as I know, seatbelts can't be safely used with those (or pretty much any other ) race seats. I'm pretty sure only harnesses will work. And,unless you have a rollbar installed, fixed-back seats and harnesses are quite dangerous. I'm not even sure those seats are safe to use, without a rollbar, even if the seatbelt would work.
You need a rollbar for protection in a rollover before you can safely install race seats and harnesses. It all has to do with how the OEM equipment works in a rollover situation.
For example: imagine your roof caving in and you are unable to move (or the OEM seat give way) because your seat and harness is holding you upright. Scary stuff.