Think about it from this angle:
If you stray from use of *defensive* violence and start your first step on the path to "Revenge", you lose your....for want of a better description, "Karmic Righteousness."--when you fight only when you have to, Karma has no quarrel with you, for the most part.
If you take it to the level of Revenge, remember that like attracts like and ( especially in the case of a gang mamber) it just gets worse, because now it's no longer baout "stopping a threat" or "staying safe" now you and the other guy and his who-only-knows how many FRIENDS, get caught up in the misplaced need to "win".
If you take that FIRST step, you HAVE to be prepared to answer to yourself if you are prepared to take the FINAL step.
Are you, truly, honestly, prepared to take him, his friends, and any/all of his family who may come back on you for this and take them all out? Even if you somehow, in whatever way, manage to do this, Will the obvious repercussions be worth it to you? To the people in your life who care for you, or for whom you may be responsible? What will this do to you? What will this do to them?
If you cannot answer yourself that you are truly, honestly, prepared to take the FINAL step, don't even take the first.
Please consider it.