I highly suggest going to and calling PCI Race Radios should you need any help with a Lowrance unit. They are an amazing company and sell all of the Lowrance products. Scott (the owner) races a Trophy Truck in SCORE (baja) and knows more than most when it comes to mapping and plotting a course. They do some off-road upgrades to certain GPS units helping keep the internals intact over very rough terrain. They also sell certain course maps (i think). On top of that, their customer service is really good and there hasnt been anything I needed to call Lowrance for that PCI couldnt answer.
http://www.pciraceradios.com/
