Classic case of 91 tach problems... I'm getting to pulling it out and replacing the resistor, but before I just go tearing into things, I figured it might be easier to hear from experience how is the easiest way to remove the dash, etc. without breaking things?

 

Well, since no one else answered, I'll answer my own in case it might help someone else...

91 RS (assuming 90-92 are the same)
Remove the headlight **** by pushing little tab on the backside of the **** itself in where the lever goes. Remove knee padding from under bottom of dash by pulling 2 trim plugs and removing the torx screws underneath. The gauge trim ring unsnaps the whole way around save for 2 screws, one on either side of the steering column. Take out these 7mm screws and then there should be enough play to access the plugs on the back for cigarette lighter, rear defrost, fog lights, etc... unclip these plugs and bezel should come free. Gauge cluster itself is very simple. There are 4 more 7mm hex head screws, remove them and tilt top of cluster toward you... as you do this the back will slide away. This got me at the right angle to slide the whole unit out from behind the steering wheel to the driver's side. You'll need to adjust the tilt on your steering wheel to get enough room throughout this project, but other than that, it all comes out as one unit. No wires, only 2 terminals that merely contact with the printed circuit on the back of the gauges... If i'd had a detailed explanation like this, it would've been a 5 minute project with no cut on my thumb. Hope this helps someone!

 

this is exactly the information I was looking for, thank you!