I dont really think impact is an issue, considering the rubber takes all the 'hit' and the ball never really hits a flipper at high impact compared to hos the ball (leaving the flipper) smashes into the nearest post or target etc.....
The main issue would be the wires from the leds down thru the playfield that are pivoting with every flipper action, causing early breakage....this could be remedied by using bushes/brushes on the flipper shaft, with lots of modding :-)

Another option is to use RGB leds, so the colours can chang with certain bonus levels or achievements, or even change colours to the music etc.

MM.