There is an official rock version of IKAG (it sounds much better in HQ)
I've had that one on my iPod for years as Track 13 on OOTB, but it's not the same as PWT. The remix she uses just now is more electric rock or something, I dunno, not good at music genres. Whatever it is that guitar sends chills down my spine whenever I hear it.
That remix and the Hot n Cold rock remix both completely destroy the standard versions tbh.
Finished watching RiR. Had good moments but some little things were a mess and she was always out of breath. Favorites: acoustic part and Firework. Overall great show, loved her energy.
10. Firework
15. Roar
16. Dark Horse
45. Teenage Dream
46. I Kissed a Girl
54. Wide Awake
55. Last Friday Night
65. Part of Me
66. Unconditionally
70. California Gurls
73. The One That Got Away
80. Roar
85. Unconditionally
87. E.T.
99. Hot N Cold
114. Firework
120. Legendary Lovers
121. By the Grace of God
136. Birthday
186. The One That Got Away
191. Thinking of You
196. Waking Up In Vegas
Albums:
3. PRISM
7. PRISM
11. Teenage Dream: The Complete Confection
14. Teenage Dream
31. One of the Boys
115. Teenage Dream
LFN getting the biggest boost of all TD singles (sans Firework) and she pays it dust
PRISM tho
EDIT: TD snatching LFN's wig WUIV charting, flawless anthem
(it sounds much better in HQ)
WUIV charting, flawless anthem 
