custom LED tail light project

Hey guys,
I have a little project that I'm doing. I have cut out the back of the tail light bulb housing of my car and I'm making some LED circuit boards to fit in them. For the running lights, I have wired in each of the circled groups below in parallel, and each group has it's own resistor. all three connect together before the resistors and at ground.

Each bulb is rated at 3.2 volts I think, I'll have to look it up again, but it was 3.?volts. Anyway, I am trying to figure out how to make the brake lights brighter. I have connected the 3 bulbs on the side in series, so that I can connect all of the other bulbs together (as one parallel group) in series. So three individual bulbs, and one LED group all connected in series. If that makes sense. I want to make the brake lights brighter, and I'm hoping that they will be when they are connected in series. Will they be brighter or dimmer? Anyone have any ideas on making them brighter?