As she herself said, this was her worst Rarity performance. If you want to see her best, check this out: http://www.youtube.com/watch?v=vlTdcpt9-FI

And BIG thanks to noideasfornicknames on deviantART for the beautiful fan art of Brutalight Sparcake used in this video: http://theinvertedshadow.deviantart.com/art/Brutalight-Sparcake-372248526