eluder

for now i'm tryin to get my basics up and running again...so far i've purchased the memphis m class 5.25" components, and a pana cq-c5210u head unit(i know, it's low end, but i'm strap for cash right no)
i have my old concept 6.5"'s in the back right now...not soundin to good
but i need some info on installing the 6.5's in the back
should i cut the back to fit them, or make a molding for them to rest in...??