Changing iphone 4 font glass?

My iphone 4's front glass is cracked and i bought a replacement one of the internet. I'm worried that after i assemble the new front glass onto the iphone, i would face some problem. For example: will the response of the touch screen be slower than usual as i'm using a fake and not genuine glass as a replacement… Or will anything happen to my iphone such as any faults?

Well, I had to resemble my iPod front panel because i accidentally broke it. Just make sure to watch the (highly liked) videos on YouTube. Make sure to listen to everything they are saying, use the right tools, try to not apply TOO much pressure, go step by step with what the video is saying.
Make sure you have the right tools and everything.
If you had done everything right, the screen should be responsive.

I know how uneasy it can feel once you've purchased a new iPhone screen, and you have no idea as to whether it will work or not
For the iPhone 4s, you can only replace the complete screen (LCD+ front touch screen). There's absolutely no way you will be able to separate the touch screen from the LCD.
I' have heard of this new site that's about to launch called iscreensfix.com
They specialize in iPhone and iPod screen replacements, and offer guides, videos, 24/7 one on one help, private members' section plus several extra bonuses. They can also refer you to where you will need to buy a new screen and if you ever get stuck, email them and they'll email you back right away.
If you'd like to take a look, follow the link below:
www.iscreensfix.com