Telephoto lens for Canon G12

[ariera]

Hello.

I need to know how good is the Ziekos 4.5x lens that might be adapted to the G12:

• Is Ziekos product reliable ?
• Will it match easily to the present lens ?
• Any influence on the camera performance ?
• Do I need to re-setup the menue after hooking up the lens ?

Thanks
Arie Ravid