Velkommen til GTA5-Mods.com

@Spadge Has been aswered before. Its not that easy in current development status. It also makes future updates more complicated as you have to setup everything for 2 cars at once.

@Cilia_17 @KOREAN-BEST This one's been touched on before. You need Ill gotten gains dlc to hear the engine sounds. McLaren F1 uses FELTZER3 sound - thats why you can't hear it. There is a link in comments to download this dlc pack - http://corepacks.com/index.php?/topic/8926-updategta-5-all-dlcs-updaterpf-6171-exclusive-files/ . If this helped, please give us 5 stars rate ;)
Alternatively you can change sound in vehicles.meta to the car that is in your game version (f.ex. F620)

@DefendMyCereal Well, from what should i start? :D Find section: <PoolName>Vehicles</PoolName>
Following lines are responsible for this:
<PoolSize value="900"/>

<PoolName>VehicleStreamRequest</PoolName>
<PoolSize value="150"/>

<PoolName>VehicleStreamRender</PoolName>
<PoolSize value="140"/>

<PoolName>HandlingData</PoolName>
<PoolSize value="800"/>

<PedsForVehicles_Base value="130"/>

<PedsForVehicles value="130"/>

<VehicleMemoryMultiplier value="800"/>

<VehicleUpperLimit value="200"/>

<MaxVehicleModelInfos value="900"/>

<MaxExtraVehicleModelInfos value="450"/>

But i can't really point you out which of these lines are responsible strictly for addon cars. I guess you need to do it through trial and error method.

@DefendMyCereal It gives you ability to have more than 14 addon cars ingame.
@Elysium911 Well you can do it by yourself. Its easy - you need to change only one word in vehicles.meta . It should look like this: <audioNameHash>FELTZER3</audioNameHash>
You just need to change FELTZER3 for the name of the car that is in your patch (f.ex. F620)

@Atomic_Wolf_ Well there is an option to use "mods" file. It's only used by game when you install plugins from Open IV. These plugins are located in "ASI Manager" option. If you want to go online you can simply uninstall them and everything should be alright. Try to search in google "mods folder open iv" and you should find what you are looking for.

@Protox Read previous comments - there were some people with the same problem. You probably don't have legal copy of GTA 5. This car needs some files from Ill gotten gains dlc. There was also a link in the comments straight to download site.
@Alphanegro We will add it in a near future. Glad you like it :) We are also working on implementation of 3rd seat but its not that easy.

@DOMSlayer Its because it collide with McLaren P1 made by AIGE. We will release a minipatch to fix this.
@Alphanegro Thanks for this info :) We will fix this with our minipatch.

You can expect new update within 30 mins.

@Machyna Thanks :)

@Lemm @Qsolution @bgracer Check my previous post

@JDM Cyfr Gameconfig is responsible for allowing the game to run more than 14 modded cars
@spence531 Do you use AIGE McLaren P1 mod?(some numbers attached to car modifications may collide)
@Genralkilla That may be the same problem as above.
Try to delete other car mods and see if it crash again. If that will help, than we will make a fix.
@bgracer It may be the problem with your computer setup. If not than there is also a possibility that you don't use a legal GTA 5 copy (there are some common problems with pirated versions).
@Qsolution It sounds like you use pirated version of GTA 5. I suggest to try downloading dlc packs from @netherbawss235 post - http://corepacks.com/index.php?/topic/8926-updategta-5-all-dlcs-updaterpf-6171-exclusive-files/
@Lemm In theory, we could make this McLaren F1 to work as a replace car but it would be way more difficult. As you can see there are planty of modified files in our mod. Then there is also problem with headlights and other things like seats, number of doors, automatic spolier (which we plan to implement in the next updates) etc. However the biggest disadvantage is that there isn't in GTA 5 any similar car.