Just bought a 113c hd and wanted 2 know if I have the most detailed map of erie, factory loaded or do I need to buy a chip? if so which 1? Thanks

My opinion is that I like the refined maps found in Navionics and Lakemaster over the maps on the HD.
I would suggest running the boat on your lakes of choice and seeing if the the maps give you the detail you want. The loaded maps have lots of information, but in my opinion, lack the precision of the newly surveyed maps on the chips.
Take care,