It would be like going from a bad LiPo to a good quality LiPo, your not going to notice the difference untill you make the change. You'll notice a bit more power and throttle response if you use Motor wire over cheap radioshack wire, but unless your an upper class driver the difference may not feel that vast to you. You cant learn to be the better driver without using the better equipment though.
As far as handleing issues, thats more for 12th scale and 10th scale WGT cars where the motor sits on the rear end and is seperate from the part of the chassis that holds the ESC, if the wire doesn't flex the rear suspension doesn't work properly