Link to the Steam page with download links
A demonstration of the mod
What does it do?
Every character got at least one new costume, a lot of them even more (e.g. Ken and Ryu have 4).
It's purely cosmetic and does not change game mechanics!
Also, the main menu music changed to 3rd strike intro, every stage has new great music (from Killer Instinct new and old, F-Zero,Tekken 5, MGS Rising Revengeance and more), modded stages (Europe and training stage) and more stuff is changed and gives the game a new fresh touch but is still playable online and offline!
I've tried to not get mod which confuses you (had to remove Links Hyrule sword and replace it with the knife so it's playable) so it's still playable against good players.
Optional:
Cvs2 ui mod
USF IV Remix
I recommend buying Ultra Street Fighter IV (not the digital upgrade) so you get the important dlc costume slots 1-3 (which are mostly modded).
Otherwise you only encounter them online.
There is currently a Humble Bundle with USF IV!
Get it here!
Only costume slot vacation and animal packs are untouched!
Screenshots (more on the way):
http://imgur.com/a/JKT3S