How can I tell what calipers my 2006 SE Off-road uses without pulling off wheels. also please advise which size and thickness of pads/rotors to use.
Trying to order the correct parts

You can measure the rotor diameter. If the rotor is one or the other the caliper will be the same make.

Bosch rotors are 320mm = 12.60in. (approx.)

Akebono rotors are 350mm = 13.78in. (approx.)

I have a Bosch sticker on the inside of my brake (on all four) which I can see by looking around the back side of my wheels.

^ as Scot said... nissan was handy enough to put a little sticker on the inward facing side of the brakes for the BOSCH... not to sure if they did the same with the Akebono...

Something you might want to look into is that 06's made later in the year use 07 braking system. so you might want to call the dealer and give your vin so they can tell you i found out the hard way.

^the production month and year should be in the driver's side door jam (so no need to call dealer with vin, unless you have a good raport with your dealer).

If you give this date to the helpfull people at R1concepts then you will be golden!