Can I use home audio speakers in Car

I am planning to buy Pioneer DEH3050 CD receiver to be used in my car.

The receiver power is: 50 watts (4 Ohms). Now I wish to add speakers to it. I am interested in 2 channels only.

I have been using JBL CS 100 surround and centre speakers for home audio purposes. But for the past 2 years, I am not using them at home.

Here I need your advice and expertise.

1. Is it possible/no harm if I use them in car audio with Pioneer CD receiver?

2. If no harm in using them, then which (surround speakers or centre) combination would give better sound quality?

3. Should I use surround speakers (left and right) in parallel or not?

The specifications of JBL speakers is given below. They come in original MDF enclosures and are not very big in size. Which means that they could be placed easily on the tray in the rear.

* Surround Speakers (Left and Right): Impedance: 8 ohms. Recommended Amplified Power: 10-50 watts. Frequency Response: 100Hz-20kHz. Weight: 2kg each (including MDF enclosures).

* Centre Speaker: Impedance: 8 ohms. Recommended Amplified Power: 10-100 watts. Frequency Response: 10Hz-20kHz. Weight: 4 kg (including MDF enclosures).

thanks in advance

cbs