Has anyone had problems with vibration and noise anywhere between 20 and 60mph? I also seem to have a dead spot at around 30mph where it just groans when i try to accelerate it just up 40mph. I also seem to have a humming sound at 40 and at 60mph.

My problem is similar to yours. I have a '04 with 55k mi. After a making long road trip I heard a grinding noise at 25mph that sounded as if I was stuck in 1st gear but the vehicle was actually shifting correctly. At about 40mph it became a loud humming sound with a noticeable vibration that seemed to come from the trans. area. After seeing the dealer they found a rear wheel hub bearing had failed and had to be replaced. There were none in stock so there was a day lost in waiting for the part to come in. Runs okay now I just hope that the other side holds up. It seems as if these vehicles are hard on bearings in fwd's and awd's from other owner's posts.

the 04's had noise from the rear differentials due to incorrect pinion depth. If it changes or disappears altogether during deceleration, thats probably your issue.

I had a bad vibration in the front end that seemed like transmission problem. Although my brakes were locking up for no reason while going down road. Found to have a bad master cylinder. After the dealer wasnt to spend 3500 dollars to replace all brake companents.

if the brakes were "locking up", it is probably due to someone placing the incorrect fluid in the brake system.
doing that will cause all the rubber componants to swell, and apply the brakes as you have said. replacing just the master cylinder will NOT fix all the problems if that is the case.