So I bought my 04 RX8 middle of last year and when i bought it, it had a lot of aftermarket parts on it. Now as embarrassing as this is, I really dont know much about cars so I dont know what all hes done to it other than the obvious.

Car has a turbo, intake, exhaust, pulleys, intercooler, possibly headers, etc.

I started the car one night with no problems. Next morning I got up to go to work and it wouldnt start. It acts like its trying to start it just doesnt crank. It just makes the loud buzzing noise without the cranking. Someone please help!

Also, I have a problem where once the car is warmed up, if it's above 2k rpms and i push in the clutch it will stall out. I have no idea what could cause that. I've recently put new ngk spark plugs in, spark plug wires and bought a new battery.

Sounds like the battery is dead. First off, clean all the connections and have the battery load tested and charged if needed. After you get it started , check the charging system, should be putting out 14.25 volts.

After the new battery it still won't crank? Did you replace the coils when you replaced everything else?