Rigid_EVO Difference between 03 & 04 signals

I've been searching and searching for the differences between the signals of a rigid and rubber mount (besides the appearance/look).

I like the options available for the 04+ much better than the bulky baseball sized/shaped signals from the -03 models.

Can someone tell/show me the differences? Is it a wiring change? Mount change?

Any help would be great. I really want to go to a much smaller bullet style light (black preferably) that still has good light output.

Thanks!