Unless the tf300 is different to the One X the files are in /sdcard/Android/obb/com.gameloft.android.ANMP.GloftA7HM
Inside this directory is a bunch of .bin files and an archive called main.101.com.gameloft.android.ANMP.GloftA7HM.obb
To access the files you need you change that .obb extension to a .zip and open the archive on your computer. DO NOT UNPACK IT. Just open it and navigate to /data/DeviceConfig/ and unpack DeviceConfig.xml It should be 22.15kb
This is the file that tells your device to pretend it's not as good as a Samsung Galaxy S3. Can't imagine why that would be....

I would imagine the Tegra tablets like the tf300 are classified the same as the One X and use the settings labelled 'Android_Medium' Edit the settings to suit your requirements but do be careful not to go too crazy. Some settings will really send the game for a Burton. A safe bet is to copy the S3 settings and w ork from there. Go with 'true' for the high quality shaders on cars and buildings and turn reflections on for starters.
Now, this is the key bit. The file you finish with must be EXACTLY the same size as the one you started with. If a setting changes from "false" /> to "true" /> be sure to include an extra space. Tweak the spaces until the file sizes match. SAVE A BACKUP OF THE ORIGINAL DEVICE CONFIG FILE!!!
Save the edited file to your desktop and drag it into the /data/DeviceConfig/ archive. It will take a long time to copy across even though its only 22kb. Finally, once the file has been copied and compressed you must rename the archive back to .obb from .zip or the game will want to download the 1.4Gb of data again. Every time I've done this the game has told me it needs to install another 1mb of data before it runs. As long as the file I create is the same as the original the changes seem to hold. Not sure what it downloads and quite frankly I don't care. Now the game runs as it should and looks lush.
Fuuuuck you Gameloft!!!!
Sent from my partners TF300T - That's what your mum said!!
EDIT: Thanks go to Hamdir for doing this. I'm simply spreading the luuuuurve.