said by pflog:Some of the carriers like to show that you're on 3g all the time (Sprint) or that everything better than edge is 4g (T-Mobile) on the stock firmware and the modded will actually show the correct signal you are using and a more accurate measurement of the dBm vs. bars compared to the method that the carriers use to measure the signal strength but you are correct in saying that there is no way to boost your actual reception with software. Just adding on to your already informative post.
These apps are nonsense. The signal strength is a function of the hardware radio (mostly) and the radio firmware (less so). Userland apps can't change this (even with root). The same goes for ROMs. People who claim better signal levels with a particular ROM either are seeing a) purposely modified RSSI/signal bar calculations or are b) experiencing placebo effect.
This app is great and will show you the actual RSRP, RSSI and SNR. Much more reliable than "number of bars". At the very least, it's free and would be able to tell you these other apps you're looking to are bogus.