I've replaced most of the bulbs on my 245 with LEDs inside and out. Superbright LEDs is pretty helpful and has high quality bulbs. For most applications it's great - they stay cool and are brighter for turn signals, parking lamps, reverse lights, and brake lights (though replacing the third brake light with an LED sets off the bulb failure indicator).

The headlights are another matter. I've tried and returned a couple of sets. I haven't had a problem with fitment - you just identify the bulb in there and look up headlight LEDs that match (though you may have to watch out for clearance issues behind the bulb because of the built in circuitry). Here is where I've been dissatisfied:

-The ones I've tried don't really put out any more light than decent brand new halogen bulbs. Maybe less.
-Because they're made from several directional sources rather then a single unidirectional source, the beam pattern doesn't work as well. They put light where I don't want it and not where I do, despite manufacturer efforts to address this issue.
-Halogen bulbs have a nice warm colored light. For other bulb types you can often find LED replacements in 3000k, which is comparable. I've wasted oodles of time in a vain quest to find LED headlight bulbs in a nice color temperature but can't find one below 5500-6000k, which imparts a nasty blue tint to the light (3000k LED is sold for fog lights but is straight amber). Plus, it doesn't look stock, if that matters to you. Of course, if you already have a body kit, a spoiler, and a side exit straight pipe you may want this.
-CRI: color rendering index, or how good the bulbs are at producing a full spectrum of light, seems to my eye (no testing equipment involved here, so consider this anecdotal) to be much worse in LED bulbs than in halogen bulbs. Low CRI is unnatural and unpleasant. It's like looking at things in monochrome. Sometimes the colors of an object you can see on the road are an important clue to what it is and that can be important at night. If you're only getting lighter and darker blue reflections it can be harder to tell what you're looking at.

If anyone has found an LED headlight that resolves these issues, please post links.