Should I install the play disc or not?

I hear both sides of the story. "Installing both discs will improve performance" or "Playing from the disc is best". I've come across a few threads that say to install the play disc to a USB drive. Will the Xbox 360 even read from 2 different sources at once?

Someone please clear this up for me, for all of us. Do I Install the second "play" disc or not, and why?

It all started with this tweet from Rockstar official Support:

For optimal performance, we recommend not installing that disc. We will have more info on our Support Site at launch.

In their official support page they wrote:

I know Grand Theft Auto V has an 8 GB mandatory install. If I want to install the Play Disc too, through Xbox Home (dashboard), is that possible?

For optimal performance, we recommend only installing the Install Disc, and not also installing the Play Disc to the Xbox 360 Hard Drive or USB drive via Xbox Home (dashboard). You will be prompted to install the Install Disc the first time you boot the game.

Yeah don't install the second disc. Just install the first one and keep the second one in while playing so it has two places to grab data.

Digital Foundry did some research and found no performance penalty if you install the play disk to a separate USB flash drive while having the install disk installed on the main HDD. Performance seems to roughly match streaming from the DVD drive so the main benefit is doing away with the loud xbox DVD drive noises.

You can see a video demo of the two modes side-by-side here:

Well technically having it on two different sources is still two places, and I've heard putting the play disc on the hdd is optimal since its where all primary streaming comes from, and having the install disc installed on a usb drive separately as its the base content; not the immediate textures, etc things like that. Yes it reads from two different sources.

The game plays much smoother with play disc installed on hi speed usb drive.