Hissing from injectors

I got two aftermarket injectors to replace two stock ones and after the install I noticed a hissing noise. I know all of them are seating properly, I just don't understand why it's hissing.

There is one noticable difference between the aftermarket and the stock ones. I noticed that the aftermarket injectors have a shorter spray nozzle thing than the aftermarket ones. Could this be my problem? The aftermarket nozzles are roughly a quarter inch shorter, but the rubber boots still seat properly.

So if you can understand, I'm thinking maybe the shorter spraynozzle is causing it to bounce off the walls of the opening and instead of spraying, its just sticking to the walls and dripping down?

I don't understand why this would cause it to hiss though... any help would be appreciated, thanx in advance.

Also, does anyone know specifically where I can get injectors that look EXACTLY like the stock ones?

Nissan, or the scrapper...possibly Napa...Are the old ones completely shot, or can they be cleaned??? 8)

as long as its running right, dont worry about it. if any one asks, tell them its your supercharger or something like that??

For the injectors i got some at nappa and they look pretty much the same. For the hissing, i have the same problem. Doesnt seem to do any harm but its annoying as heck. I cant find out whats wrong either but its no biggy.