Easiest radio install?
 

Decided to put a cheep touch screen raido in the 04 Rx8. I’m not really wanting to spend the $150 for the fancy wiring harness thing being this car is just my drive to work car but the stock raido is shot and I gotta have tunes. I was looking at some old post and it they were talking about the climate control being apart of the wiring for the raido or something like that, or the display for the climate controlled. I’m not really concerned about the display not working but will the ac and heater still work if I just hard wire everything myself IE the + - 12v turn on and all the speaker wires. I’m not concerned with how hard it will be or even the steering wheel controls. Or do I have to have the metra kit thingy???