Speakers? Amps? Wattage?

[squirrel]

Ok so I'm new to all this, just got my first '89 MK1 GTi Cab, its an amazing car in great condition. Only problem is crap audio.

So, here's the situation.
I have bought a new Head Unit - Sony CDX-R6550
I have bought new speakers - 4 x Infinity 6402cf 6 x 4's

Now what I need to know is what power of Amp should I get to run these?

I've been reading a lot of stuff about amps and speakers but I am kinda confused.

The output of the head unit is 4 x 40W.
The RMS of the speakers is also 40W.
What should the RMS of the amp be?

I'm also considering getting some speakers for the boot, I don't want to have overpowering base, just improve the sound. I was thinking of getting 2 x infinity 6500cs and amping these also.

Any advice would be gratefully recieved.

Thanks

[Dizzie]

get a 4ch 4x55w amp to run all those. If the amp is mega overpowered compared to the speakers you can turn the gain all the way down and get better quality than running a smaller amp on the limit.

your headunit is rated in MAX output not RMS btw.

[squirrel]

Thanks for the help.

I've decided to get two of the Infinity 6500cs 6.5 inch speakers for the boot, these are 90W RMS.
I've found a 6 Channel Infinity(5760A) Amp which will do 4 x 55W and 2 x 107W RMS.

Will this amp do the job of powering all the speakers?

Do I have to consider low or high pass filters?

Any advice would be cool, thanks.