What
@Jim_Tod said basically, ask them not us.
The largest size on their website for Fuji large photographic prints is 49.5" wide. Now I don't know if this is the largest sheet of paper they do or just an example size/price that people rarely go above. You would think that from a printing point of view the height of the landscape image would limit the print size due to the physical width of the printer. No such issues with yours as it's very low. (Next time consider shooting your pano images in the vertical)
To answer your question though assuming your native resolution at 100" wide is 300ppi then it will literally look as finely detailed as a single native resolution print from your camera. Just a lot wider. I've had panos printed by dscl that are 49.5" wide and they look excellent.
Word of warning though if you are new to printing I'd recommend you crop out at 300ppi say a 12" x 8" from the pano and order a test print of a small section of it. To make sure your workflow is good and you are happy with it before committing to the expensive pano.