Glad to hear this. As yesterday I debated with an individual on how "bootloaders would improve battery life." This would prove my point that if it resolves issues with reception, it would overall improve your battery life due to the phone working less hard on getting reception.
+1 to bootloader helping the overall performance of the phone.
Also, the bootloader would work on any version of ICS as long as its the Galaxy Nexus. Kind of like radios, a new radio is presented with a new version but it will work universally. But the best performance would probably come out of using it combined with a 4.0.3 (or above) ROM.
-- If you actually need to get in contact with me just tweet me rather than PMs its more efficient and I can get back to you faster.
Nexus 5 (D820)
: Purity | Franco Kernel
Nexus 4 (E960)
: Carbon | Franco r193
Older devices: Galaxy Nexus, ASUS TF101, Nexus S, Samsung Vibrant, G1