Shimano 8000

Can anyone tell me the difference between Shimano 8000, 8000C & 8000RE.
I have an 8000C & would like a matching reel for my second rod. I bought an XT8000RB but it’s a much larger body & unsuitable. Any help appreciated

To my knowledge, there's no such reel as a Shimano 8000. Whatever reel you have will have either a name, some other lettering and numbers or a combination of all/some. Depending on the model concerned, it might not be particularly obvious what the full name/number might be. However, if it's relatively recent, the best bet is to look at the reel foot. If it's a bit older, that probably won't help.

As a stab in the dark, I'll take a wild guess that your reel is possibly a Shimano Baitrunner 8000 OC (Oceanic). The full model number would be BTR8000OC. If it is one of these, be aware that there's a possibility that they have recently been discontinued.
Shimano Baitrunner Oceanic Reel | Angling Direct