Help, my Cats are driving me crazy!!!!

I am in desperate need of help. I have two cats they are part Tabby part Siamese. We have had them for almost two years now, and their behavior gets worse by the week.
--my cats walk around the house and cry and cry and cry, so loud that the downstairs neighbors scream. They are healthy cats. I know it is in Siamese blood, but they are sooooo... loud and it is constant. They cry at the doors to go out, but they never go out. They cry in shower for the water to be turned on even though they have water.
--they crew EVERYTHING!!! cords, socks, boxes, carpet, shower curtains, they even chewed through one of those thick water jugs. I've used every spray imaginable, they don't seem to mind the nasty taste. They have tons of toys throughout our home, and I am only gone for seven hours a day, the whole reason we got two cats was to prevent boredom. When my husband and I are home we play with them and give lots of affection, but they will chew on anything right in front of us. Water in their face doesn't bother them, yelling doesn't work, we've even tried a swat to their bottom, but they just go right back to chewing.
--the middle of the night they whine and destroy. We live in an apartment so there is no where to put them to keep them from crying at our bedroom door, and when we leave it open they chew the cords for the tv, jump all over us, leap at shadows on the wall, and attack our legs/feet and each other.
I don't want to get rid of the cats, but I'm running out of ideas, we have reached a point that we would like to have all their teeth pulled and their voice box removed. Please somebody help!!!!

Are they fixed? Have they done this since you got them? What were the circumstances you got them under? Do you have any cat trees or something for them to climb. Any litter box problems? If you can give some more background it may help some of us to help figure out what the problem is.

Yes, they are both fixed. We don't have any litter box problems anymore. After we got them fixed, our mail cat would urinate all over our stairs and at the top of the staircase, but I placed their food in the spot at the top, now we don't have any of those problems. We got them from the Humane Society when they were 3 months old. They just told us that the previous owners didn't want the kittens of the mother cat that they owned. They have been like this since day one, they just have progressively become more persistent. They have a climbing tree. We also have a huge box for them to chew, but it doesn't help. They eat Eukanuba and are completely healthy. I've asked the vet but they just tell us that physically there is nothing wrong. Hope this helps you, b/c I can't wait for suggestions

You know, it sounds to me like a stress reaction. Cats are very particular about everything and even little things can upset them. Some of it can even stem from kittenhood. While I know a bit about behavior modification, I don't do it full time and it sounds like you may benifit from an organization that helps with these sorts of problems. They were started to help enlimate pet abandonment because of behavioral problems. If you contact them, they will call you back and spend as much time as you need on the phone to figure out what's causing the problems. Give this web site a look, you will also find a lot of good info there as well as the contact info.
While teeth pulling and devocalization are options now days, you can find ways to work with them to avoid it.

http://www.catsinternational.org/index.html