Bowyer

I have looked online and tried wading throughout the how-to section to no avail. I'd like to find a comprehensive DIY video or write up that outlines how to change a fuel injector on my clk430. I think I have narrowed my problem down to the #4 injector. Any particular brand or place to purchase one that is recommended? Autozone doesn't sell them but could order 3 different manufacturers...and they ranged in price from $49, $109 and $200 each!

Thanks for any help you can provide!