Quote:
said that socalled high intensity bulbs were not a real improvement over stock, but halogen tail bulbs and led 1156, 1157 were a significant improvement and recommended.
Oh, hooray, another hobbyist magazine article advising people to go out and do dumb, illegal things to their cars' lights. It's like a flippable-paper version of the SEMA show in Las Vegas. 
"LED bulbs" do not ever work safely or effectively, which is why they are illegal. This is the case for any "LED bulb" in any taillamp originally designed to accept a filament bulb. The problem is with the concept, not with any particular design(s) of "LED bulb". See here (whole thread, all links). See also here on AllPar.The halogen 1157 (etc.) is also a poor idea. All of them sloppily made; filament is never in the right place. I've never seen one that isn't massively overwattage (50/15w is typical, where a stock 1157 is 27/8w). This throws a 100% overload on the circuit, which in addition to the obvious dangers that poses, also makes the stop lights very slow (in relative terms) to come up to full intensity, which severely degrades the safety performance of the stop lights.
The only halogen bulb worth using in place of a regular one in any of our cars' signal systems is the #796, which is a 35w halogen bulb with filament in correct place to replace 1141, 1076, 1156, etc. in reversing (back-up) lights. The slight extra wattage combined with their short runtime, only while you're reversing, and the lack of any consequence to a slower rise time, mean the large improvement in rearward seeing is gained with no negative consequences. 796 produces 62 candlepower; 1156 and 1076 produce 32 candlepower, 1141 produces 21 candlepower.
More on rise time: you want the stop lights to come up to full intensity as fast as they possibly can -- that gives following drivers the maximum possible time in which to react to your having applied the brakes. Zero rise time is ideal, and LEDs provide that, but again, they have to be properly engineered; an "LED bulb" has zero rise time, but that does not compensate for the severe deficiencies in the rest of its performance.
For those who lack the tools, expertise, and equipment to make their own safe and effective LED lights, and who are wise enough to avoid the fast-talking profiteers—think SEMA again!—who pawn off this kind of garbage (long ugly thread), but who gotta-just-gotta have LED lights, you can sometimes get clever with ready-made truck/bus LED lamps placed inside the lenses of your car's original lights. You have to be careful to get the placement right; they need to be upright, facing straight, without any slant, tilt, or inward or outward rotation (the exception is the units made specifically for postal trucks with a 7° forward tilt to the rear surface where the taillamps are mounted). If the units you pick have a "TOP" marking, it must be at the (duh) top. My favorites are these, these, and these, in clear-lens variety when available. They are inexpensive, well made, and give very good performance. Another good option (smaller but more costly) is these:
If you try a project like this, make sure to select units meant to produce the correct functions. Front turn signals are not the same as rear ones (fronts are brighter), for example, and tail or marker lights do not serve as adequate stop lights, even though they might both be red. There are some fairly esoteric exceptions and asterisks to this caveat involving the smaller round LED units linked and pictured in this post; if anyone actually pursues it I'll get into it with them.
