GT is too easy and I want to do challenge runs. Either gameshark codes to make AI cars harder, or sim tires only, or some combo of both. Problem, I can find next to nothing on Sim tires online. Most sites just repeat what the game says, or says don't use them because you have less grip and slide around.
Are sim tires more realistic?
Are they playable or something untested?
Will it be a fun challenge or just needless frustration?