two 4 channel amp. should i bridge?

hi there,

i am new to this forum, however, i couldnt' find any info regarding this question.

i have 2x 4channel amp to power my front and rear speaker.
so basically, one 4 channel amp is powering only front speaker(mid+tweet)
Another 4channel amp is powering Only the Rear speaker (mid+tweeter)

both amp is about 400w, (guess)


Front door is using Alpine spx-17pro.
Back door is using alpine spx-13pro

here is my question, should bridge both of my 4 channel amp, so each amp will power 100% to front and back speaker?


is there advantage by doing this? SQ wise ?
Since Alpine Spx 17pro is a 4ohms speaker. if i do bridge my amp, that will decrease ohms from 4-2 right? will that damage my speaker, what kind of result will i be getting
with 4ohm speaker to bridged 2ohm amps

would i be better of with just a single 4channel amp to power front and rear speaker instead, of using both 4channel with bridge or unbridged ??
manythanks
:)