Yep, it is a gutted LIM. My plan was to have the tune done, but never got around to having enough money for it. The CEL comes on for the VSS and the front Pre-Cat. The cat material was fractured and breaking apart so I removed it. MIL eliminators would correct the CEL, or you can get a new pre-cat.
I did a recent tuneup on it and I was getting no misfire readings. Not sure what to say about the fan issues you mentioned first. Right before I delivered the car to Ron I replaced the radiator overflow tank, because the original had a small hole in the side and leaked. It might be a little low on coolant.
If you can make it up to Monroe sometime I can swap out the LIM for you. In regards to the IMRC. If you put the LIM on yourself you will need to take the spring off the end of the IMRC cable. That spring pulls the cable as if it were connected to the LIM. Without it you would get a CEL for that.
That offramp issue is what happened to my car getting on 520 in Woodinville off of highway 9 at Costco. That's a fun onramp.
I would be happy to help all I can. Just let me know. I miss the car. This miata really sucks in comparison.