I have both the Mopar winter front ( and a custom made bug screen to match for the summer ) as well as the Espar. The Espar is rated at just over 17,000 BTU vs the 750 Watt block heater. IIRC thats about 6 time the heat of the block heater. For those who don't know about these they are designed to preheat the engine, just like a block heater would do, but runs on diesel fuel. If you don't have a plug in where you work or are away skiing for example you just program the timer to come on before are to leave ( a max of 2 hours ) and when you start the engine it is already warm ( max 160*F ). The temp will be determined by the outside air temp. Even if it only heated your engine to 70* and it say -20 out thats a lot better than starting a cold engine.
Espar make a version specifically for the 03-09 Dodges. It bolts to the tabs on the inside left frame rail just in front of the fuel tank. You don't have to drop the tank to install a fuel pick up tube. It sucks fuel from the sender by installing a "Y" in the fuel line. You just pull off the line on the sender that goes to the engine and install the "Y". You will need to keep your tank at least a 1/4 full in order for it to work, but in the winter you shouldn't let it get low anyway. If you leave your heater mode on defrost and the fan on low it will not only warm up the cab but helps keep you windshield clear also. WARNING Don't leave the fan on high as the heater running for 2 hours will more than likely kill the batteries. It will work on 4 th gens also but since their wiring is different the cab heat part will not work. I asked Espar why and they told me Dodge stopped giving them wiring diagrams. You can use the universal one on older Dodges or any diesel powered vehicle or machine.
It comes with a 24 hour timer, although you can get a 7 day version also. If I wish to leave home at 7 AM I would, depending on how cold it is, set the timer to come on 1 or 2 hours before. When I get to work I push the preset button on the timer for the second starting time and it comes on at 3 so that when I leave at 4 PM again I am not starting a cold engine. There is a third preset time also.
I've used mine even in the summer sometimes. Say I am camping in a valley and it is cool in the morning I hit the manual start button and let it run for half an hour or so while I am getting ready. That way I am not pulling the hill with a cold engine.
They do cost a few bucks, up here they are over a grand but my engine is worth it.
Can you tell I love this thing

BTW I detest remote car starters as all they do is encourage people to let their vehicles idle and you are still starting a cold engine. With a modern diesel idling will never warm up the engine as it need heat to burn the fuel efficiently.
Oh yeh getting back to winter fronts the Mopar or Geno's version are IMHO the better style as you can open or close at will, compared to grille inserts. Shad