I have purchased some new cheap off brand injectors on e-bay and also got a new bosch to try. None of them were any good the spray patterns were terrible and some of the cheap ones dripped and shot a pencil stream. So I just put my old ones back in tested them with the fuel pump relay bypassed and my old original silver mercedes units had an excellent spray pattern!
What a waste of money!
Test your currently installed ones before you jump into this I have talked to some techs that said they had to go thru 10 new injectors before they found a good one. Also replace them in sets so they all have the same opening pressure.
You will just need 8 small glass jars to compare all your injectors spray patterns., and bypass the fuel pump relay ,on my car after you pull the fuel pump relay jumper pins 7&8. this will run your pumps.
All injectors should open at the same time when you push on the air mass meter plate and they should have a nice fine mist spray pattern no dripping no shooting to the side or pencil streams.
Hope this helps. dont cheap out! it bit me