The Elite 5 only uses Navionics Micro SD charts in the "Gold" series, so some of the higher resolution (Platinum and Platinum plus) charts are not available.
But I believe that the "Fish n'chip" charts are available in micro SD, and if this is the case, then you can get theses which have better Bathymetric material, which will show better bottom details.
Also Navionics may have updates of the chart chip--or you may find a micro SD specifically for your region--and that may have more detail than the general map for the entire US.
I would give Navionics a call, and find out exactly what is available for your area in the micro SD format.