Sirius questions, please help!

So I want serious in my car and I had some thoughts about which way is the best way to go. Maybe someone had either done or wanted to do what I want so they can give me advice.

1. Replacing the stock stereo - Losing the steering wheel mounted controls is something I don't want to do but having a cleaner look and better sound is nice. I'd just get a sat ready radio and the sirius add on kit and I'm good.

2. Using the PA20-TOY - My car came with this. I was going to rip it out this weekend but then thought about using this with the Sirius Starmate and putting it underneath the radio in that compartment. I'd still lose the mode function with Sirius but it would still work with the radio and of course the volume button still works for both.

3. Can I just get an add-on kit (Less than $100) to make the stock stereo work with Sirius? This way everything that's factory installed would still work but I feel like this option is expensive.

If anyone else has any ideas how I can incorporate Sirius into my Prius I'd like to hear it!