It is possible to do some modifications to the stock projectors to give it some color at the cutoff, but you won't get the flickering color when seen from different angles. It just has to do with the optics of this light, and it's not designed to do that.
I second to not waste your money on "purple" bulbs. They're give you less usable light, will probably burn out quickly, and are just a waste of your money. Just get some HIDs.