Firstly are you using the trem floating? What guitar are you comparing it to? What gauge strings are you using? Is the bridge raised 1/8th off the body like the recommended spec? If its flush then you have work all the spring tension holding it in play to do a downwards bend.

The idea is you can use less springs if you need to. So try that first and if not get some black springs for an American Standard Strat and try them (you shouldn't need more than 3).

Check as well if the trem claw is straight or at an angle. The higher the gauge of string the less tension you want on it. So if its angled tighter on the larger strings your fighting them each time you use the bar.

One other thing is you could be just wrenching on the screws. A 6 screw bridge if screwed down may require you to loosen them. Some people loosen the 4 in the middle further so they function as to just keep the bridge affixed. They adjust the outer two screws as pivot points.

You can damage your guitar if you adjust these incorrectly. So best to observe closely when you use the trem if the bridge is fouling against the body limiting your trem range (bladed trems were made to overcome this prob). I would get the opinion of a tech/luthier if this is the case. It might just need a proper setup.

Everything Shockwarrior said.
Also if you look at American Standard or Deluxe instruments, they use black trem springs.

These are a lot less tense. It's not always a bonus having low tension springs. They dont offer the same benefits on returning to pitch.

Also there is no real reason why you should be struggling so much with the trem. My insticts tell me your trem claw (the bit round the back that the springs attatch to, and has a ground wire soldered to it) is screwed into the body too much. Simply unscrew it (same amount each screw) until your trem is easier to use.

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No no and no

You might want to re-check your intonation after your adjustment (if you haven't already )

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-thanks, done!