iam about to install my avic f900 and wanted to know if it is absolutly necessary to hook up the vss and reverse signal wire. if not using a back up camera.

No, it is not necessary. It just helps the nav work more accurately, especially in areas with limited satellite signal. If you don't want to hook them up, don't. And if in the future you decide the nav isn't as accurate as you'd like you can always hook them up then.

I havn't hook my vss wire up yet, for those of you guys that did hook up the VSS will the bypass still works? Such as changing stuff in the navi while driving.

Yes - bypass will work fine with or without VSS and/or reverse wires being connected.

iam about to install my avic f900 and wanted to know if it is absolutly necessary to hook up the vss and reverse signal wire. if not using a back up camera.

What car do you have? maybe the wires are easier to find and get to than you think

i got a nissan 2006 frontier w/o the fosgate stereo... the vss wire is behind the speedomiter and the other is w/ the engine i didnt hook it up and my gps still is acurate as hell and it still knows when im speeding. I guess if i was in BFE it might come in handy but i will live. dont wanna tear my dash out