@FearlessFizzy yes, the only thing you need to do is reduce the 'InitialDriveMaxFlatVel' values back to the original ones.
Or even easier, since this mod only change 2 values (this one and drag coefficient one): pick up the original handling files from gta and only change the drag coefficient (the second value from the lines), reducing all values by 10 times (that's what this mod do, plus increasing the DriveMaxFlatVel value, but what definitely makes the 'unlock' stuff in the top speed/acceleration is reducing the drag coefficient)
@frouchi do you have any other mod installed?
@Abdulhanan2008 there are too many cars on gta V at this point for me to make it, I don't even have time for it now. but you can test it yourself in the game, for it, I recommend the NFS gauge speedo mod: https://www.gta5-mods.com/scripts/nfsgauge-rpm-gear-speedometer it have a very good chronometer for measuring cars stats.
and for spawning the new DLC cars I recommend simple trainer: https://www.gta5-mods.com/scripts/simple-trainer-for-gtav it covers all vehicles from the new DLCs
(if you are willing to do this list, I will post it here and give you the credits in the mod description)
4.7 All in one file version, by @thalilmythos
only one file to replace, all vehicles included, file location;
@thalilmythos thanks a lot!
@Louielam00 do you use Open IV?
@thalilmythos can't access the link you posted, it's not opening. but someone already talked about it in the past, but I was not sure if it would work. if it does, it would be very welcome. I can't do it right now, don't have time, can you do it? for sure I'll give you the credits in the page
@JezzTorrent do you have any other mod installed?
@kaloskwok for sure is some conflicting problem (there's lots of reports of ot), some new handling file from the mod affecting another that you use (this other handling mod you posted is not updated in seven years, much fewer files/lines to conflict)