This link below has this text: "The supervisor engine is hot swappable, but packets are not forwarded when the supervisor engine has been removed. When a supervisor engine is reinserted, the system reboots."
http://cisco.com/en/US/partner/products/hw/switches/ps4324/prod_module_install_config_guide09186a0080194171.html#41784
So, looks like if we proceed with replacing the supervisor engine in slot1, we will experiance downtime, even though we have a redundant sup in slot2. Or, is the link speaking about a scenerio where we will have only one supervisor and no redundant Sup.
