If you get a full limited bumper with the flares then it should fit. You just need all the brackets and the bumper lamps. Not sure if those will plug into the 99 harness. I thought about doing this swap since I do have a jdm bull bar. Haven't decided on it yet though.
Ebay works though. They all are about the same quality, not great, but cheap. A junkyard pull is preferred, but most 4runners in my area die head on it seems.