Firstly, I have an F-700bt, CD-SB10, SC-C1, Ipod Cable, Software bypass hack.

1) If I'm cruising down a highway or road... at random the unit will cut all the sound and the voice will come on an tell me "You Are Over The Speed Limit". Sometimes this will happen when I'm doing 5km/h over or 50km/h over.

Would this be an issue with the VSS wire?

2) Also, I took apart my dashboard to install the Ipod Cable and a wire was hanging down - the mute wire. Can this be grounded to the chassis, or would this cause conflict with my bypass hack or anything? I use my bluetooth cellphone a lot and would like to make use of the mute function.

I had the unit professionally installed and the more I look into the how it was hooked up, the more corners I find that were cut... so I wanna make sure I do this properly.

Thanks.

The speed limit is a setting in the unit. Go into the settings-->Nav Settings and you can modify it or shut it off completely.

The unit isn't hardwire bypassed so the mute wire shouldn't be connected to anything. Don't ground it. If you want to do the hardwire bypass, you need to relocated the mute wire to a different pin prior to grounding the wire, but you make it sound like you did the software bypass so you should just leave it be.