Nachritter, yes, I will take some photos soon. This weekend I should have time during daylight hours. I notice you have a 2000 VW Jetta. Is that what VW Golf's are called in the States? Yes, sure, watch this space: pictures will be forthcoming. I should complete the installation this weekend, if not before.
The battery charger part was dead easy. The charger is a CTEK MXS 10.
CTEK MXS 10 Car Battery Charger - the smartest battery chargers in the world!
I got the most powerful charger available that was reasonably waterproof (and that means without a fan of course!) so only 10A. It seems to work well. Also this charger has a temperature sensor, and a specific AGM setting, so no risk of undercharging in winter or overcharging in the summer if I park in the sun.
As for the timer, well a timer would be great if I had a 9-5 job and drove off at the same time every day. But I don't, so I got a little radio-controlled relay and key fob remote activator. The plan is to fit that inline with the coolant heater, so when the mains lead is plugged in the battery is always on charge and I can activate the coolant heater from my bed ;-) or a half-hour or so before driving off.
If you have more regular daily habits than I do then a timer would be ideal, but if I were doing this again I would look at getting an even simpler self adhesive oil sump heater pad (from Wolverine or similar?) and wiring that up together with the battery charger so it is on all the time. Much, MUCH easier to install and less to go wrong. 100w or 125w should be about right, depending on your local climate.