I originally bought the three PS2 games. Vice City was my favorite, but the disc got scratched to hell. GTA III and San Andreas got "borrowed" permanently. So, I went into Walmart earlier this month and bought The Trilogy to replace my old games. Pleasantly, GTA III seems to be exactly the same as the original release. It allowed the GameShark to work, so it must've been unchanged. More than I can say for VC.
You might have heard about them censoring things "offensive to Haitians". I expected that, but there are more differences than just censorship. The weapons have been renamed, and there are various oddities, like the police car radio sounding garbled as if being played in a slow motion voice. In fact, it's so distorted that it's indecipherable. My old save is incompatible with this version of the game. I was thinking about starting a new save anyway, so I begrudgingly went along with it.
Days later, I had forgotten how I beat the vigilante missions the first time, and I was having difficulty because the police car has awful handling and GTA drivers are total idiots. So I said "**** it, I'm using the GameShark for infinite mission time." I tried to use the code, but the game didn't start up. I'm sure you can guess why. That was my breaking point.
Not only am I now contemplating forking out more money for a sealed original version of Vice City, but I get the feeling that San Andreas will be worse. I posted this just in case anybody else gets suckered into buying the boxed set. Neat packaging, though.
The version differences aren't anywhere near as bad as requiring to get a rarer version of the game. I own this game for both the PS2 (original version) and the PC, and the PC version has some of the differences you described, asides from maybe the police radio issue. I can still hear them just fine. I remember barely being able to understand them for a while on the original PS2 version though. That, and the PC version actually fixed the Hyman condo hidden packages reward glitch, which is really nice.
In any case, if you're having issues with the vigilante missions, either wait until the availability of a tank (after completion of "Rub Out", you can steal it from the military during a 6 star wanted level) or use a glitch to get to the second island early and get all the hidden packages between all islands, then use the unlocked Hunter helicopter to finish it via its R3 mission. (might take a few tries for you to actually get off Fort Baxter with the Hunter unscathed. I find I have the best success rate if I take in a chopper coming in from the North to limit soldier spawns as much as possible).
You can also technically use the 90 hidden package reward to get the tank earlier via island hopping glitches, but I think it puts you in greater danger of getting shot full of holes since it's in the middle of Fort Baxter rather than at the north end like the Hunter.