So, I've already laid down the Dynamat Extreme on the back half of the car. The front drivers and pass floor were Dynamated and two layers were used over the pass floor hump to help with vibration and noise from the cats. Behind the rear seats got the treatment as well.

Doors are next on my list for a full deadener treatment.

Question is what else can I do to help reduce noise? I heard neoprene works well but what kind? How thick? Where can I get some? Any other options I should consider?

 

try wrapping wires and cables with felt tape and also putting it over panel clips and places where doors latch together

this is the material and you can get a better idea from the pics
http://www.ebay.ca/itm/280989826261?...#ht_5864wt_984

 

Try this from second skin
Luxury car quiet with our noise insulation products Luxury Liner

 

in some areas you might benefit from also putting extra layers of carpet under the flooring (areas like where the cats are).

 

I have new carpeting going in and two layers of dynamat over the cats now.

Would a layer of neoprene help with noise reduction?

Which type?

Thanks.

 

Do I need to put this on the sides on the sub well and rear trunk area (where the Dyna Xtreme is) or just the "flat" parts of the car(floor and rear hump)?

Thanks

 

The proper way to deaden is:
Vibration damper, using dynamat, alpha damp, fatmat etc.
Decoupling, using a 1/8 thick closed cell foam pad.
Blocking airbourne sound like exhaust noise, road noise etc. You would use a Mass Loaded Vinyl.

More info.
Welcome to Sound Deadener Showdown | Sound Deadener Showdown

 

I would only put it on the floor part of the car, but some people put it on the ceilings or what not.