eManage Ultimate self-tunes on a 2JZ, why not the 350z?
 

So I've been reading up on the eManage Ultimate as I intend to buy one in the immediate future and I've found that on the Supra engines the EU self-tunes when a wideband o2 sensor is plugged in. Would it be able to do the same on a 350z?

yes

Really?!?! Thats very interesting. Do tell more please. :D

The eManage Ultimate has an AFR Target Fuel map which you can link up to either I/J Adj Map 1 or 2 (Fuel maps which directly modify injectors). Pretty much what it will do is when the engine meets specific conditions (that you specify) such as > 90% throttle, specific water temp, etc - it will map out conservative values in your fuel map to reach the AFR goals you list in the AFR Target map. This is only used for WOT and it's only used to initially street tune your motor when a dyno isn't available. You also have to have a wideband O2 device (Innovate LC1 for example) properly connected and functioning with the EU to one of the accessory ports.

As long as your crank angle sensor is clean and your RPMs are read properly (no spikes / jumps) - you should be alright to build some fuel maps with this function. Once you have the fuel maps that you want, disable the AFR Target mode and go with it.

Some love this option, others don't bother using it because a dyno is always the more accurate / safe method to use.