Trade.
no you can only link megaman games together if it is the same number like megaman battle network 3 blue to megaman battle network 3 white
Blue moon or red sun?
no
hit start go to megaman then go to navicust
No, it's not.
Go to the Under Square.
google them even though i dissaprove of cheating in megaman games
yes, if you have battle network 4 red sun or blue moon (PAL or USA version) and you have a EXE 4.5 battlechip gate you can play operation battle, there for you must have Navi Chips (only released like exe 4.5 in Japan, or you can buy them on Ebay) and battle chips.
http://tartarus.rpgclassics.com/mmbn4/walkthrough23a.shtml
Mamoru's room.
some where in castillo area from the net
Here is the code:993E41C6E209 B3A00AD93EOC 5840956756C1