In dash cd player

Hi, im looking to get a cd player for my civic, and i was wondering what i should be looking for on the specks if i would like to get subs later? is there anything spacific i would need on the unit? and what would be a desent yet under 200$ range? thanks!

alpine is always good no matter what you are planning on doing

but, what should i look for if i want to put subs in later?