Somehow I missed this thread the first time and I am going to revive it. I just installed my ELM327, $64 new from Amazon, and installed Torque on my Droid Thunderbolt. So far I love it. There are a couple of things that I need to learn so it works correctly. But so far I have noticed the Speed, Coolant Temp, and RPMs are dead on.
I haven't used the HUD feature that Chill described but my phone is large enough that I can have 6 digital gauges on the screen at once and read them easily while my phone is mounted on my center vent.
Right now I am monitoring Coolant Temp, RPMS, Torque, Speed, instantaneous MPG, and Boost. There is a preset in boost that I don't know what they are looking for, so I think that reading is way off. The app comes with a screen full of analog gauges but I find the digi gauges easier to read on the fly. There are so many options for info that you can display, most of it I dont know what it is or what I would do with it. The good thing about Torque is that they have a free version to see if you like the app or not. If you are paying $30-150 for the dongle whats another $5 for the app.
I will have to look up the other apps later today. One thing I did notice is that if you have Pandora installed on your phone Torque will not communicate as quickly and has connection errors.
Chill, do you know if the preset for the Boost gauge is 0 or something different? Also did you plug in the dongle and leave it, or t do you plug it in only when you use it. I don't think it would drain the battery while its connected and the car is used.
Just got this dongle in the mail today (fuck you Hong Kong), and I'm pretty sure my girlfriend will want to break-up w/ me by Sunday. Obsess much ?

Once I grabbed mine from the Post Office I installed the dongle on the side of the street. I couldn't wait the 7 minutes it would have taken to drive home and do it. My order took for ever too. Ordered Mar 19 arrived Apr 7.