#include <sourcemod>
#include <sdkhooks>
#define MULTIPLAYER 3
public OnClientPutInServer(client)
{
SDKHook(client, SDKHook_PreThinkPost, Hook_PreThinkPost);
}
public Hook_PreThinkPost(client)
{ // Note: Default is around 200.0 - 250.0
new Float:newspeed = GetEntPropFloat(client, Prop_Data, "m_flMaxspeed") *MULTIPLAYER ;
SetEntPropFloat(client, Prop_Data, "m_flMaxspeed", newspeed);
}