I tested different 1157 based LED's, most are not bright enough and 
if you point the top of the bulb at you all the LED's point at you so 
none of the light reflects inside the lens housing. I found a style 
at Truckpro truck parts store that is brighter then a regular 1157 
bulb and uses 13 LED's in the bulb. If you point the top of the bulb 
at you there is a panel with 3 LED's, around the sides pointed 
outwards are 5 panels with 2 LED's each. This allows the light to 
reflect off of the lens housing and fill the entire lens with light. 
Everyone says that these bulbs are brighter then 1157's and you have 
no heat. You will need to replace all the tailights at the same time 
because the LED's come on and off faster then regular 1157's because 
the filament doesn't have to heat up or cool down. They are the same 
size bulb as the regular 1157 bulb so you can just remove the light 
socket and change the bulb. They have worked fine with my turn signal 
flasher. The bulb is Roadmaster #CG1961R and costs $5.75 each. I have 
seen them under a different brand name, I think at Pep Boys.