Saturn/Opel Astra GTC audio newbie

[exyboxy]

Hi guys! I am very new to this forum, and I am here because I was referred to by Herc from AON.co.uk, I was told the guys at this forum could help me out!

I have an Opel Astra, rebadged as a Saturn in the USA. Not many people have these cars, so the aftermarket parts are very limited.

I would like to keep the same head unit, and the same speakers on the doors, I would like to add an amp and a pair of subs for the back. They don't need to be top of the line.

To get straight to the point:

Can I use the stock hu and add an amp/subs?

What would the procedure be, how should I get started?

Is there an alternative head unit option that I can hook up to my current speakers and a sub? Example: a device or something that is in the shape like a GPS unit with an AUX jack for an ipod, that I can hook up to an amp and the door speakers, and still be able to use the oem radio in it's current position. I don't want to remove it, I just need a device that won't require me to cut up my beautiful dashboard.

I will post pictures of the car's interior/parts at your request if anybody needs them.

Thank you in advance,

exy

[exyboxy]

Cliffs:

-Keep oem head unit and speakers, add amp and subs

-Is there an out of dashboard device that acts as a head unit with an auxiliary port that can hook up to factory speakers/subs and allow me to use my oem stuff without modifying

-Request pictures if you need visual aids of the interior

[exyboxy]

bump