The one time I used antiseize...I had issues. Stuck plugs and debris in my engine.

Sure most cars are iron heads, but my VW is Aluminum and I never have problems.
Its turbo charged and I drive like a maniac....they come out easy.

Yes or else you won't be able to change the 2 rear plugs on each side.

If you do it whole thing,i mean spark plugs replacement correct and follow all required steps then you never going to have any trouble with ECU,unless you mess up something like broken wire,disconnected ,or wrongly connected plug on spark plugs coil,spark plug is cross threaded or not threaded down all the way,etc.

Spark plugs replacement on my 2008 Infiniti G35 sedan Journey.
 

Just let you know that today i replace spark plugs on my 2008 second generation Infiniti G35 sedan and its relatively easy job to me.I always use OEM plugs in this case its Denso long life iridium plugs FXE22HR-11one of the best available on market because its utilizing two strongest rare metals-iridium and platinum,plus Denso legendary reliability.I take the cover from engine,four 10mm bolts,loose four clamps with 5/16 socket on both plastic intake tubes,what connected air filter to throttle body's,disconnect breather hose from intake tube located at driver side,loose with alien wrench #5 eight long screws on both throttle body's pull them,without taking any hoses from them,and set them aside.Plus i recommend to pull breather hose from intake tube on passenger side too its make your job easy.All that above give me clear and unobstructed access to spark plugs coils.For your convenience work on the one plug at time,dont pull them all.I use 10mm socket to loose bolt holding coil,disconnect wire harness from coil and pull coil out and away,make sure you didnt drop coil,then use 14 mm spark plug socket with long extension to loose an remove plug,throw it away,put new plug tighten to 14 foot pounds,reinstall coil with 10mm screw,plug coil harness and that's it.After i finished all 6 plugs i reattached both throttle body's with air intake tubes,put breather hoses back,tighten clamps an reinstall engine cover.My engine run after this job as a silk smooth,i love it!

Yes, but just to be sure, just pull one of the easy to reach ones and look at it to see if it's original or not.

Infiniti service and maintenance guide recommend to change spark plugs at 105 000 miles and looks like you got more 5 000 miles to ride before that replacement.

How many?
 

How many spark plugs do I need on my g35 2008 Sedan?

Well it's a six cylinder, so probably 6.