tweeter, crossover, mid bass speaker = component set, and normally come with one set.

It can be run without amp and stock HU, (depend, still better ask pro which component set suit your HU).
for TS, better sound is depend how you define?

In ICE, good sound are very depend on HU, speaker, amp, sound insulation, setup and installation. Each has it own contribution.

A component set definitely give you certain slightly better sound in the extend of sound staging. High freq and mid/low freq are separated.

High freq sound from tweeter, normally on dashboard or pillar, sound like vocal, high freq music instrument.
mid/low freq sound from mid bass, normally on door panel.

This setup allow you to enjoy vocal .. like the singer sing in front of you.

My car is using stock HU, and a component set only. Good enough for me.

So at the end it is still depend on what you want and how much you afford. and please don't go for cap ayam stuff. No money than save more. Also you can consider 2nd hand good stuff.

for some ppl,
-stock HU, stock speaker = good
-stock HU, component set = good
-stock HU, component set, amp = good
-stock HU, component set, amp, 2 layers sound insulation = good
-stock HU, component set, amp, 3 layers sound insulation = good
-branded HU, component set, amp, 3 layers sound insulation = good
- etc..

lol, so many combinations

Above explanation are very layman, and non pro.

Persona elegance, b line.

Polk audio - http://forum.lowyat.net/topic/1294170/

RM400++