Trainers / Performance Altering Game Modifications
Trainers are 3rd party pieces of software which inject themselves into the game. ...
The above is an excerpt form the server rules. I know you have probably read this, but bare with me. The operative words in the above quote are:
"Game Modifications" & "inject themselves"
So when you say "mouse fix" , if you are talking about software like 'vcsens' then the answer is No, you can not use that, or anything like it. Neither are you permitted to edit any game files to achieve the same effect. This is because 'vcsens' and similar software "inject themselves" into the game, and modifications to Vice city files are obviously "Game Modifications".
You may however modify the sensitivity of your mouse axis, on the provision that it is a system wide modification, meaning that regardless of what game you are playing, or what programs you are using (like your web browser) that the modification also affects that too. Basicly, if the modified axis affects how your mouse moves on your desktop too then it is a system wide mouse modification. For instance, most gaming mice now come with software that enable you to modify your X and Y axis. Although such software is "3rd party" it does not "inject" it's self into the game, and neither does it modify any of Vice City's game files.
Therefore, the modification of mouse axis that meets the above criteria does not constitute as a LW's server rule brake.
That is my understanding of the matter, based on careful scrutiny of the rules and previous topics posted on the matter.