Ive got myself a new roof and the 3 cables ..   Has any-one any tips for fitting diy style

i plan to upgrade my sound system, but i ned a bit of advice as i know little about stereos etc.   i have a after market cd player in my mk4 cab at the minute, and i have upgraded the front speakers. the rears are standard.   i plan to cut the panel where the roof fold into and stick some 6x9 sony explode speakers in there.   what i would like to know is... can i just run them as plain spaekers? would i need an amp?   also, i also have some 4 inch speakers n the garage, and i thought i

ok 1 of my indicators got taken out anyway ive replaced but for some reason wen indicating right thats the side that was taken out it gos really fast even tho there isnt any missing now wot can i do