Axura for the vibrant isnt necessarily dead yet, its just that axura is stable to the point that it really needs no more development outside of theming. as to a percent batt mod, all the themes for axura now have them, the most recent ones that is, i know my frost theme, crysis port and annex's themes on D4A have them, we are working on getting all the themes back on the new server. Check the link in my sig for the d4a website.
for the modem i always just used the kb1 modem, it performed about the same as the ka6 modem did for me tho.
Samsung Galaxy Nexus - GSM (i9250) - Slim Bean(latest) | Franco Kernel (latest nightly) | My_GNex_settings
(512 Read_ahead_kb | adjusted Row settings | color_settings)
Samsung T-Mobile Vibrant - ICZen (4.0.4)
ASUS Transformer Prime - Androwook
Kindle Fire - Completely stock