Upgrading a Trek bar end light

[Cemoi]

I bought a pair of Trek bar end light. Although I'm mostly satisfied with them, I'd like to replace their LEDs with more powerful ones.

Here is a picture of the inside after removing the plastic cap and the red lens:

And here are the LEDs, seen from the rear (this hole is normally covered with the red lens):

Replacing the current 5mm LEDs with other 5mm red LEDs would probably not make much difference, as they are pretty bright. I'm rather considering replacing them with one power LED (red or red-orange Seoul or Cree), hence the following questions:

• The base of the 5mm LEDs leads is embedded in some kind of epoxy resin, very hard. It doesn't prevent unbending the leads, but it prevents unsoldering the LEDs from the circuit board. Any suggestion to remove this hard glue? Melting it with a soldering iron?
• The current LEDs have a very narrow beam, which is OK because the light has to go through the small "window" in the plastic casing. So I need a powerful red LED with a very narrow beam, which is not the case for Seoul and Cree power LEDs. Any suggestion for such a LED?

 

[herulach]

Heatsinking might be an issue with power LEDs, although you can get some pretty damn bright Red 5mms. How do the domes mount? is it to provide side visibility or rear?

White power LEDs might work, but if they're too bright the red effect will be lost.

 

[Cemoi]

Heatsinking might be an issue with power LEDs

Not at the low current which this light puts into the 5 mm LEDs (probably around 20 mA each, i.e. about 40 mA if I replace the two parallel LEDs with one LED).

How do the domes mount? is it to provide side visibility or rear?

The black cylinder on the second picture (which contains the AAA battery) is inserted in the bar end. Since it is the "flatbar" model designed for mountain bikes (vs. dropbar model for road bikes) the two LEDs are directed towards the rear of the bike.

White power LEDs might work

Most of the light would be blocked by the red filter, so I'd rather find a very bright red LED (with narrow beam).