ok - so i am replacing my head unit and giving up the navi and onstar audio.

My question is - what else do i have to worry about in regards to the bose system? can i just pop out the bose speakers and put in infinity kappa's or are their eq's or amps wired in the middle.

my plan

1st install pioneer DEH-P9800BT head unit and use the stock speakers for a few days - maybe a week

2nd install infinity kappa components all around

OR
must i replace everything all in one shot? im not sure if there are obstacles that may prevent me from doing it a little at a time.

i am going to search this more but i would appreciate any advice.

Thanks

Mark