I decided to right a guide for those that are having troubling playing my mod properly. If you're having a problem and there not one of these, then ask me.
Q: I ran the game but i have white cars when i play!
A: Sounds like when you tryed to play my mod for the first time, you got the converting textures message, which delete's my textures and put's the orginal GTA3'S. If this happens, open the .RAR For my ultimategta3 mod, then extract models folder in the same folder as the one with white cars. Now play.
Q: The mod won't work. It gets on the splash screen, but then the game crashes and i hear the windows error sound!
A: You're loading a save game that was not from my mod, that was saved with a different main.scm. You must start a new game when you first play my mod, then after first mission you can save and load that save in my mod.
Q: After a while of playing, the game lags very badly, but it seems to happen when cars appear, and when there's none it doesn't happen.
A: If you're getting this, you may not have enough RAM, Graphic card is something like an intel chipset. Make sure you system at least meets these requirements.
512MB RAM
1.5 GHZ Processor
128MB Video card which is a ATI Or Nvidia.
If your system meets them, then try a disc defrag, downloading the best drivers for your graphic card, make sure there is no programs running when playing.
Also try ending all non essential processes.
Or, you could go onto task manager, click the processes tab, right click gta3.exe and set priority to high. You need to do this when GTA3 Is running.
Q: Roads, walls are taking time to load.
A: Make sure you have frame limiter enabled in options>display. If you do, you should do a disc defrag.
(From GTAForums)1.4 GHZ Processors and txd.img and txd.dir are the problem
This is not true. Textures not loading is a hard drive output. Defrag your hard drive, and make sure no programs are running.