need suggestions on good reverse camera for punto evo

The reverse sensor provided by kht fiat caffe at the time of purchase of car is not very effective(it doesn't work sometimes). Whenever I take the car for service or for some minor issues, if I ask the service centre to have a look at it, they say that I need to have it checked with the installer(fiat cafe showroom). So planning to replace the sensor with a reverse camera. If I get the reverse camera fitted from a car accessory store, will it cause any issue for warranty of the car(still two years left in warranty)?