I don't care about no cd cracks, but it would be unprofessional of MTA to endorse something that may not be legal (or at least that R* might not like), which is what they'd be doing if they added special compatibility to cracks that the original game did not have.
I highly doubt that would be possible since the blue menu is loaded 'into' one of the games after they open, and all 3 games are totally independant. If you wanted a shared settings menu/server browser it would have to be a seperate program that closes/minimizes when you choose a server and loads up the requested game (GTA3, VC, or SA).
Currently you only see the tag if you point at someone (face them directly or aim at them with a weapon), but this might change before release. There may even be options to display them differently.
There's no way for you to increase it, my guess is that they are streamed out on purpose when you move away from them because GTA doesn't like a lot of markers on the screen at one time.
Vice City isn't out for PSP. Vice City Stories WILL be out for PSP and it will have some sort of multiplyaer (probably like Liberty City Stories does). MTA will never make a mod for PSP. Get it?
If that's true then that's the reason you can't hit them.. Find a server where most people have low pings.
If you do and still have these issues, you just need to learn to adjust to the lag. Aim at where they are going rather than directly at them. Learn which weapons are effective and at what ranges.