Newbie trying to find the answer for a couple days thru searching, so I apologize in advance if this horse has been beaten to death... Will I see much of a difference in the basemap if I swap the 9MB default with the 14MB Meridian? Also, all the reviews on Amazon.com are so negative on MapSend Topo CD, I'm wondering whether it's worth it. Just disappointed in the map support in this unit.