It really comes down to measurements. It should be a fairly straight forward swap and nothing I haven't done before (of course not in an Infiniti)
Here's what will be needed:
1. 6-speed transmission out of either a G35 or a 350Z
2. Pedal assembly from same vehicle
3. Clutch assembly (clutch/pressure plate/slave/throw-out bearing/linkage)
4. Shifter and boot
5. Custom cross member(I will fabricate)
First off though, I need to get under my FX and make some initial measurements and then measure a transmission. From a quick glance, it appears the shifter location will be just about the same but I must confirm that first. I also hope the manual transmission (who knows the Nissan name for this?) is the same length as the auto. If that's the case then the stock driveshaft should work. Of course if it doesn't, I can get one made for about $400. Then I will look at the pedal mock-up and the access through the firewall for the pedal plunger/slave.
If all of that seems very feasible, I will source the tranny and parts and go from there. Mine's a 2WD so that will make everything much easier. Not sure how it will work on an AWD but can look at that later.
This is in the very initial stages though and is just an idea on paper right now. Once I get more committed, I'll start a new tread and document everything.
EDIT - I forgot to mention the current project I am involved in
http://www.vorshlag.com/E36ProjectBook.asp - LS1/6-speed swap into a E36 BMW.
