Here is a write up on how to remove the gauge cluster from the dash. Good luck! Sounds like you should be able to wiggle it out...
Gauge cluster disassemble
-2 top screws on the front , remove them tox again (short stubby attachment is easier in this situation)
-using a small flat object (screwdriver or knife) you can wedge the gauge cluster out
-3 connecters on the back, first disconnect the white than the blue and the small black (right to left) the connectors use a flip connection, where you press the tab above the arm and then flip the arm up.
-remove the whole cluster.
-5 tox screws in the back hold the back piece from the front, like in the pictures provided by delmarco
-to remove the dials themselves there are three black and white pillars... you need to turn them counter clockwise until the white part is clear of the .... lol clear part of the dial setup.. You may need a little extra help here in the form of some sort of vice grips or pliers because i found it kinda tough to turn the whole pillar (not just the white part the black needs to turn as well) the necessary amount to release the dials. Just be careful when using any tools.
Once you released the dials your set to install whatever you wish..
1997 E36 M3 - running stocker style right now...