Wendy:
I'm wondering if the lack of information on line is a sign that these may not be the best choice of instrument? I purchased Navman 3100 set of instruments based on price - while they are working - the company has changed hands several times in the last few years.
I managed to keep the instruments working by modifying the display to PC board connection - which was coming unglued due to moisture or ?... Most folks would have had to toss the units an repurchase.
So if you are local and don't plan on being "out there" for a while the instruments might be just fine... the company may be a sleeper and make great instruments...
Do keep us advised as to your choice and result.
Jay