I recently bought a 705 and had the same issues you did. The cost does not justify it and it is more of a fancy trinket than a necessity. With all the 'add ons' that I got with it, we were pushing almost $400. I never did find anything else that was acceptable. My suggestion is to save your money and get one since anything you should get now will most likely not do what you are looking for. If you are just looking for a moving map for the stoker any small cheap one that runs on batteries would be OK. With a little butchery I am certain you can hook it up to the stoker bars. I do not think the 305 has maps, so if you are looking for that it will not help. I am certain you can confirm that yourself.