Need to buy a portable xm satellite receiver

Hello Friends,
I was looking at buying the 'Samsung Helix XM Satellite Radio & MP3 Player'. I had the following questions:

1. Can I connect the Helix to my car using the built in FM Transmitter or do I have to buy a seperate car kit. In case I use the FM transmitter how is the reception quality?
2. How long will the Helix be on charge while using it in car with the FM transmitter?
3. What extra would I need to take the Helix home and listen to it there
4. If I can listen to radio using the FM Transmitter what does the car kit do?
5. Can I replace the flash memory in the Helix if this one gets full?

Here, is what I have found out after some more research.:
1. Buy a Samsung Helix from shipdog for $154 (before $50 rebate)
2. Buy a Samsung YACP100 car kit for $70 from circuitcity.
3. Install the car kit in the car for $70 from circuitcity.

Will the installation of the carkit by circuitcity be a hardwired installation or will it be a wireless one?
I would like to avoid the costly installation fee from circuit city? Are there any stores that would not charge me for the installation in case I buy the car kit from them?

If I am mostly going to listen to the radio in my car. Is there some other unit that I must be considering to reduce the overall cost?