From my understanding the XR-E R2 90 degree view angle is what made it throw better than XP-E R4's. I Build identical P60 drop-ins and had some misc lights. All things being equal the smaller view angle XR-E R2 always threw more.
The XR-E's 90 degree radiation pattern meant that its
spill was tighter, because the normal radiation pattern was pre-collimated by the built-in optic above the die. However, that optic had the same effect on ALL the light coming from the die, so the brightness and tightness of a reflector-generated hotspot wasn't affected significantly, since the hotspot radiation pattern is so narrow to start with. (The XR-E's radiation pattern was 25% narrower than a normal LED; if you apply that same multiplier to a ten-degree hotspot, you'll only tighten the hotspot by a couple degrees.)
In fact, the
brightness of the hotspot would've been
negatively affected by the XR-E's pre-collimating optic if general-purpose reflector had been used, because pre-collimating the light caused less to hit the reflector. To compensate for that effect and maintain a bright hotspot using the XR-E emitter, a narrower reflector was required, to reach further into the 90 degree radiation pattern and redirect more of the light straight forward. That's why XR-E specific reflectors are so much narrower than general-purpose reflectors.
