Please carefully read this before you sketch down the install.
Google about 5.1 system and how it works and it cant be down without dsp.
You need following stuff for 5.1 system.
Good Pioneer pre
DSP which supports 5.1, cheapest will be pioneer 6600 or 7650. Alpine H 510 if you intend to use Alpine pre.
Two way component kit in front.
Two coaxials at back
Sub in the trunk
and a centre speaker from pioneer.
5 channels of amplifier for front, rear and center, 4 channel amp for front and rear speakers, and centre channel directly from dsp if it supports or a 2 channel small wattage amp to power centre speaker.
1 channel from mono amp for sub.
3, 4 pairs of RCA
plus wiring etc.