merc4ulfate is correct, other than the Bigger Better Protractors is already in the mod. Websters S-Class Mod, while cool and really good, is definitely not compatible, since there are changes done to the boat in FotRSU already. Sound mods may or may not be compatible, and are not supported by the team at this time. All of the above probably contributes to your not hearing that merchant, and the later CTD. You will have to delete your Save folder after you remove the other mods, so that data gets re-set before you try FotRSU again...
