Car: 1990 Mazda RX7 GXL

Hey guys,

I'm working on an weekend car and I decided to freshen up the 20 year old audio system. I'm looking into an auto setup that is first of all very economical. The car is for autocross but I would like to have something decent to listen to on the way to the courses. I have an Pioneer deck that I want to utilize, I just had a couple of questions regarding hooking it up:

Head Unit: Pioneer DEH P545 (Bought in 1999)

Q: I would like some suggestions as to what speakers (6" -6.5") will be a good economical choice for what I'm looking for?

Q: I will be wiring the speakers directly to the headunit (no amps), what gauge wire do you recommend?

Q: Also what would I need to hookup my iPod to the head unit (with charging capabilities)?

Let me know if any of this is even possible, I'm new to the audio world...

Thanks in advance.