Benny's garage STILL works
Single player Apartment just got updated
Yacht Deluxe V1.9 STILL works
Premuim Motorsports deluxe by Im Not Mental will laso let you have the updated cars
use simple trainer or any MP ASI (like the one @65536 linked) mod on the website to allow for update cars for spawning
you can either make a map with map editor or use I'm not mental or szabo (forget name) persistence mod for them to be parked around you
plenty of shit to enjoy single player with, not to mention LSPDFR, Rage Transportation, FiveReborn, pretty much any script to give you a job, like Simeons repos, Tonyas tow, FireFighter mod, etc...