World editor problem and skins problem and a question

Hi guys, sorry for my total STUPID AMOUNT of posts lately. Anyway i pause physics, go to world editor and try moving vehicles with vehicle movement arrows, and it lags and goes ALL over the place. Is there any way to fix that? Please let me know.

Another problem, i tried making a West Coast Police Department S.W.A.T skin for the D series and the skin won't import to beamng drive. Is there any way to fix this? Let me know.

And a question, I watch crashboompunk destruction nation and other beamng youtubers and I see that they have high quality modern exotic sports and super cars. So i tried looking for the higher quality and even the normal cars like Mercedes Audi and other car companies. And i can't find the high quality ones. And i can't find the Porsche 918 High quality spyder on world of mods or any other cars on world of mods! Does anyone know what im talking about here? And if you do, can you please help me?