Decided to switch out some of the bulbs in my 745 to LEDs earlier today. Nothing custom - just bought the plug-n-play variety from an online retailer (superbrightleds.com). The 1157's are the 24-led variety (red and amber). The 1156's are 19-led (red).

Here are a few discoveries to share:

The good
- No heat, should not need to replace ever again, and as long as the sockets don't wiggle and lose contact, you'd never have to touch 'em again at all.
- Instant response. On is always full bright, off is always full off.
- No amber blob visible inside the front turn signal assemblies.
- With 24 LEDs bulbs, the load was enough not to trigger the bulb-out sensor for either the parking circuit or the brake circuit.

The bad
- With barely any load on the flasher, it will do the "fast flash". A dummy load or a solid-state flasher is required in the circuit.
- If you have side marker lights wired between the parking and the signal lights, you definitely need a dummy load. Current is drawn through the circuit for the bulb, and LED bulbs otherwise are one-way only when it comes to flow.
- While they are brighter than incadescents straight on, they are still dimmer off angle.

The ugly
- Because the 3rd brake light socket is mounted at an angle, these bulbs will not work because there's not enough light scattered out the side. In my case, only the left half of the 3rd brake light got lit up.

I have not played with any of the white LED bulbs to replace the backup lights. Based on the performance with these colored LEDs, I expect their performance to be largely the same in that they'll match the stock lighting, but not much more beyond that.

As with everything, your results (milage) may vary, but this is my experience with 'em.

-- Kane
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Blossom II - '91 745Ti/M46 ... Bubbles - '74 144GL/BW35 ... Buttercup - '86 245GL/AW70 ... The Wayback Machine - '64 P220/M40