It's not a case of ripping or stealing it's a case of copying and if you copy a design, to answer your original question, will it harm you from a selling point of view then yes it will greatly harm your chances of making a sale and it will greatly harm the price you can sell your services for. More importantly it will also greatly harm your reputation and reputation is something you only get one shot at.

Now if your being inspired by something and go on and create your own work thats fine but you have to determine the difference between copying and inspiration. Way too many people put blatant copying down as 'inspiration' when it's obviously just not the case.