90 300 E Fuel Injectors

I have a 90 300E and my local shop says that the reason my car starts rough is that the injectors are not holding the fuel while the car is off. He says there is a pump that keeps a small pressure on the fuel to keep it ready to fire upon startup. And that when they leak some fuel into the cylinders, its like a mini flooding. And that's why it starts rough. It runs fine once its running.

Ok after all that....

My question is...I see the fuel injectors on line to purchase and they are not that expensive. The injectors seem pretty easy to get to on this straight 6....

Is changing the injectors something I could do myself or are there many tricks that could cause alot of problems if not done right.

I would like to try if it's feasable.
Maybe a good shop manual could help?

Thanks
Steve