MTA team is not so strikt to the servers... That is why MTA:VC is fool (yeah, fool) of modifications...
That is why there are tones (compare to all number of active servers, of cos lol) of crashers, spawn vehicle servers, etc...
We do not support those modifications, but give players possibility to change skin on MTA:VC... For this - modder should send me the file and image of skin he did... If it is decent skin, like Gollum's cop skin - we'll post it on site...
SA:MP is more strikt to its servers, that are using SA:MP... That is why, according to general politic of SA:MP we do not allow ANY modifications... The one hack we allow - camerahack for movies... And in future - it will be allowed ONLY on movie server...
If you think it is stupid - ask yourselves the next question:
When Rockstar* will develope the multiplayer - you also will ask this company why the fuck you cannot play with the modified game???