Performance differences between 4-1 and 4-2 exhaust

[fulcrum]

Hey everyone, im thinking about upgrading my stock exhaust on my CB700SC. Either this, or painting it. Regardless, the stock exhaust has seen better days. The only current manufacturer of an exhaust system for my bike is MAC and they offer a 4 to 1 where as my stock is a 4 to 2.

Now, understanding that i will have to re-jet my carbs, will I notice any performance issues by doing this? Will it improve performace or take away? Also what can I expect for the sound of the exhaust if I went to a 4 to 1?

Any input would be greatly appreciated. Thanks