how to tell when the upper control arm bushing are going bad and is it hard to replaced?

thanks

 

That's kinda hard, i think the best way is to look under the car and see if the bushing is torn, cracked, or compressed in any unusual way. The bushing may not be too expensive, i'd say an aftermarket piece would be about $20. However, since the car is still fairly new, you may be only able to get the OEM bushings, which are very expensive(up to triple the price in some cases. Your best bet is to see if the dealer will cover it under warranty.