If anyone would actually take the time to read the V-LEDs article there is an easy way to modify the stock flasher to work perfectly with the LEDs and yet still give you a quick flash warning if one of the LEDs ever actually goes out.

Or as others have mentioned replace the flasher. It is super easy to replace just turn the flashers on and follow the sound with your hand until you locate the flasher then without removing your hand turn flashers off with free hand and remove.

Oh and yeah 2 x 3ohm resistors on the rear will do the trick as well that is what I have installed. That is why I was a little confused when you said you put resistors on the front.