What does `想要` emphasize exactly?

Question

So far I know 想 means want to e.g I want to know or I want to have. 要 is more like must or need e.g. I need to go or I must go.

Is 想要 more like 想得到 / 想有, that you want to get something, you want to have it, even you don't need it? Like you want to have a car on your own but you will never leave your room. That's the meaning to want to get or want to have to me.

or

Is 想要 more like 需要, that you need it even you don't want it? Like you need a pen to be able to write, but you don't really want it. If you don't need to write you will never buy a pen, you prefer buying a car. That's the meaning of need to me.

Answer 1

想要 means "want" regardless of whether or not you need.)

需要 means "need".)

Like you want to have a car on your own but you will never leave your room

你想要車，但你不需要車。(You want car, but you don't need it.) (Want and not need.)

我想要去廁所。(I want to go to toilet.) (Want and need.)

So use 需要 to describe when you really need.

Answer 2

想要 + n: want to get/own something

想要 + verb: want to do

Answer 3

想要 can express 想得到/想有/需要. Whether you really need it or not.

e.g.

我想要吃東西 could represent "I'm hungry" or "I want to eat something even I'm not hungry".

Answer 4

想要 ≈ 想 - want/would like (to)

我想要吃东西 ≈ 我想吃东西

要 on its own is usually "want", not "need", but a bit stronger than 想/想要. However, 要 can also mean "will". 我要吃东西 could mean either "I want to eat" or "I will eat", depending on context. It would never mean "I need to eat".

需要 is always "need". 我需要吃东西 - I need to eat.