Hi, new-ish Firepower owner here, and I just did my very first LED conversion! Woo hoo! I used the Ablaze 4-SMD-LED bulbs from Pinball Life, and color matched to the inserts. WOW, what a difference. I really like blazing color, and those LEDs did not disappoint! The conversion was really easy too. I tried some Ablaze 1-LED flat top lens and they were too dim for my taste, very much the same level of brightness on the original incandescents.
Also, does anyone know where to obtain a left slingshot plastic? Mine has a big chunk taken out of it and it is one ball hit away from cracking into two pieces.