Technical differences seem to be few, technically do not know, but the performance seems identical. The fact that his GTM25 list more stations will only benefit if they are Navteq Traffic that can be tuned from the parameters of the signature. Any other station in the FM Table to appear and that is not indicated by the signature can disturb the setting of the correct frequency. In this case the GTM26 may offer some advantage because it would provide less interference tune.