DragonEmi, it is entirely possible but extremely difficult to do this along with a lot of other hacks using packet editing; but it'll take a lot of testing and decrypting.
IF, but only IF, you are just joining a random server, that is not owned by you or by your friends, and that is not modified to have in it hacks, then you, as a client, can't do what the OP wants.
Instead, if you are the hoster (have full control of server, FULL), then you can easily modifie the server to give you advantages.
But again, only IF you have FULL control of server.