[Designed to simply clip onto the habit-trail with power being sourced from the box at the back left of the cabinet--installed in minutes with no permanent modification]
This mod uses a strip of 15 LEDs underneath the Spine Tunnel, triggered by a custom integrated switch (modified rollover), with a fade out powered by a 4700uf capacitor. As this custom trigger is housed in the arch, the timing is always perfect regardless of how the ball travels through the ramp (this can be observed around 25 seconds into the video clip below as the ball hesitates through that ramp shot, but still times the tunnel interaction appropriately).
I'll update later on with additional video once I have more variations to show (namely pink to red and white to red). Pink to Red and White to Red will have a brighter initial flash of light when triggered. Other colors could potentially be requested, but the nature of the mod is best suited to a red (blood splatter) finish