Hey guys, well i recently purchased a 2005 Chrysler crossfire from a dealership under a powertrain warranty. I have the car for about 6 months now, as of late the car has had a loud ticking noise under the hood, and it increases as i accelerate. Soon enough after the car started losing power and it would have a hard time getting up to speed when i press on the pedal, not to mention the noise being loud in idle and even louder during acceleration. So i took the vehicle in to the dealer, they've had it for about a week to diagnose. And today i am told that i need 2 O2 Sensors (Up) and (Down),A Catalytic Converter, and a new throttle body sensor. (However i was told that new sensors come in new throttle body, so maybe is should just upgrade? Does anyone have suggestions? Where is the best place to purchase these parts? Are these jobs that can be done myself?
Any help would be greatly appreciated!

- And today i am told that i need 2 O2 Sensors (Up) and (Down), A Catalytic Converter, and a new throttle body.

- Where is the best place to purchase these parts?