I find I can't hear Maemo Mapper/flite over road noise. So I'm thinking of getting this amplified speaker. It's 1.2 Watts per channel. (I haven't found online what the N800's is to compare.)

DX also has this one, which has other features and is larger but also is rated at 1.2 watts/channel. (I would have wanted this one before I had the Tablet, but seems redundant now unless it were louder.)

There are a number of complaints on the forum about flite being too soft for in-car use (at least for car's like mine!), but I haven't seen any remedies. My experience with using an FM transmitter to hear it through the car radio hasn't been great, though that might be the specific transmitter.