Ok,please correct me if i am wrong ... i think that all the mods i tested that change the performance of cars make a little mistake concerning top speeds : those top speeds we see on the onboards videos are lower than the in the vanilla game because cars were tuned that way for the specific track ,and also taking into conisderation the fact that each team try to get a balance between quali and race !
I think that those speeds in vanilla game (time trial ) can be reached in real life if teams go for a 100% quali setup !
So,in my opinion it's useless to limit the top speeds in the game,modders should rather play with the acceleration and DRS effect only ! and if possible the handling of cars at different levels of downforce !