Galaxy S Advance Android update

I've heard there are some Android alternatives. Like miui or Cyagenmod or Mozilla OS . I have Galaxy S Advance (GT-I9070) and i've heard Samsung is not going to provide any updates for my device. So, i got a few questions i should ensure before i done something stupid: * if i install something from the mentioned above, shall i lose my guarantee/licenses? * if i decide to install the software, should i perform some rooting of the device or something? * if i do decide to install the software, what's the best one which shall not slow down my device (as i noted android 2.3.6 to be slow) * could i use ICS update and shall it slow down my device or not?