OT: XM Questions

I know that there are people here who love their XM or Sirus radio, but I have a question. I just bought my XM radio receiver from Walmart today and have started my subscription. If I ever decided to bit the bullet and buy a car stereo or home stereo with the XM built in, do I have to take out a separate service for each one, or can I use the same service for each component? I know I'm going to love it, but something tells me I might be happier if I actually bought a stereo system for my car that is XM ready. What do you guys think?
I decided to put it in my Mustang, but dang it, I already have a blown fuse for both the cigarette lighter and the adapter input. Not sure how that happened! I guess I can use it in my Sentra until I replace the fuse in my Mustang......
I decided to put it in my Mustang, but dang it, I already have a blown fuse for both the cigarette lighter and the adapter input. Not sure how that happened! I guess I can use it in my Sentra until I replace the fuse in my Mustang......