will this fit in to the s2k?
Pioneer In-Dash Player (DEHP4800MP)

and does it have a good sound?

Also, do Pioneer speakers have a good sound? Is their big improvement in the 02?
Another question
Do these speakers work in a way so that you can use the audio buttons above the start button...

Thank you

 

single dash - yes it will be

good sound? too vague of a question to answer. it wont sound terrible.

to use aftermarket players with the left side controls, you will need DCI adapter - read the FAQs

 

Yes that HU will fit. and you will need a DCI to keep your dash controls.

As for the speaker question... you really need to give us more info about which speakers your talking about. Pioneer has some great speakers and some just ok speakers.

I can get you setup with the HU, DCI and speakers. I can wire the HU so its plug and play for you.

And depending on the speakers and the model year of your car I can get you setup so that install is also very easy.