You won't be able to play with other people who do not have the same modifications that you do, because all players on the same server have to have the exact same database files, to prevent cheating and multiplayer errors (of which I've seen some duzies... think a Kilo launching an Udaloy DD from its tubes
).
Although if you don't play online or you have a copy of the stock or common modded database as a backup to install when you go online, it doesn't matter.
