I can't help you with your question but I too find it interesting that there are more maps software than just one. I have stated before I have the portable I-Way 500C unit by Lowrance. It uses a hard drive and is up-graded using the Internet. I do know my unit now has Canada with the most recent revision (no Europe but could be available?)
Having just purchased a new Nitro R/T just last week with the built in GPS unit I was surprised to see a new local extension shown on the Nitro unit that has never been on my I-Way 500 that has received two revisions this year.
I did not received any CDs for the Nitro GPS and when I asked the Salesman how the unit was up-dated he didn't know.
Does anyone know how the factory unit is up-dated and how the Owner can keep it up-to-date, and what manufacturer builds it?
Nitro Year: 2007 (1 of 91,815 sold in 07)
Nitro Model: R/T 4X4 Stone White
CAT-BACK Exhaust, CAI, Projector Head Lamps
Fully-Equipped w/all factory options