I bought these:
They are exceptionally bright and easily visible as turn signals. I am impressed by both the brightness of the forward facing LEDs as well as the remainder, which reflect off the inside of the housing nicely. The 1156 version works just fine with our cars, you just have to file down one of the stubs on the side of the bulb. I know this sounds a little shady but it fits perfectly once you do this. Since these do not have built in resistors I add them separately for an extra $5. After this they did not throw any codes.
*I would not
advise buying the 18 LED version! I bought these perviously (in amber) and was not comfortable with the brightness.
*Swithback LEDs usually utilize the 1157 bulb types because they have dual contacts on the bottom. This bulb type (1157) will not work!
*In case you find a switchback bulb type that does work (which I haven't): Keep in mind that switchback bulbs only light up half of the LEDS at a time, so a 60 LED switchback will be about as bright as a 30 LED bulb.
*Lastly, for those of you who are thinking about getting bulbs with 60+ LEDs, remember to read the width dimension! Some of these will not fit inside the headlight housing.
Hope this helps!