I have the Colorado 400t. To save batteries I use the same 12v cable that came with my Nuvi 350. It powers the 400 and does not send it to mass storage mode. As for City NT 2009. I downloaded it and then used map installer that comes with map source and placed it on a 2gb sd card then put it in my 400t. It only slows it down during boot up not so bad during operation.