Is it safe to buy a car tru Yahoo Autos?

Im buying a car tru Yahoo autos, and the method of payment is tru Western Union. The instruction is to submit payment tru Western Union and payment made to a Yahoo agent in West Palm Beach, Florida. To confirm the payment receipt I will fax the Western Union payment receipt to (xxx) xxx-4315. Im just curious if this is the safest method to pay the car instead of using Paypal or other secured payment method.