Game crashes after replacing cars

[ZENESYS_316]

Hi. So I downloaded some mods to replace a few ugly cars and some good cars,and it seems like something isn;t going right. I noticed something,I can only replace upto 5 cars,6 is ok but crashes sometimes,but 7 cars is crashing everytime. Idk what's causing this,is it that some car mods aren't compatible with "ANY" car? Like I put Audi R8 to replace the Jaguar XKR,this isn't causing issues,but if I go to a higher class,or something,idk what's causing these,the game crashes WHEN LOADING TO A RACE! Mostly happening to higher class cars like Murcielago as I am using Reventon to replace it or the LPX version of Murcie,Diablo as I am replacing it with Countach,CarrerraGT as I am replacing that with Mantide,CLKGTR as I am replacing that with CCX or Gumpert Apollo or something,mostly...how do I stop this from happening? The game also sometimes crashes when I am choosing cars. I think either my pc can't handle mods cz it's too dang old(16 years...ouch) or could be broken files or textures,cz is some cases the car's textures gets fkd,idk what's happening...pls halp >:0