@crashmaster: in the end we decided to go in El Salvador as well and we had a great time. And the borders in and out were quite easy and professional. When we wil reach Panama I am thinking to write a "About crossing Central America borders". Until now we never used helpers... hope to keep it that way.
@Tom: hmm if I only knew how to make prints from the road and send them in the US... you would for sure receive one :)