I'm planning a build for my '04 t4r and I'd like to have suspension that I can adjust the height of from inside the cabin. I'm pretty new to researching parts for a t4r, but from the bit that I've done, it appears that getting Bilstein 5100's, airbags and an air compressor would do the trick. Has anyone put a build like this together? I'd be interested to hear how it worked out, what they liked and didn't like about it.

I don't believe a suspension like that exists. Why would you want that? Reason you may think?

5100 fronts are adjustable by clips on the shock themselves, to change the setting you have to pull the assembly apart. Rears are non adjustable, you can place airbags inside the rear coils to help with heavy loads, but it really doesn't change the height.

Height adjustable rear suspension was an option on 4th gens, but it didn't do the front. It was intended for leveling the vehicle if you had a heavy load. I have a factory switch for it if you want.
I haven't seen anything for the front.

I would suggest investigating the Land Rover LR3 and LR4 systems. They have full ride height adjustment.

(Jeep & RR) offer proprietary suspension systems that can be used to adjust ride height in the vehicle but i haven't seen anything aftermarket.

I mean you can adjust the drive train on the fly

If looking for an example, the Lexus LX and some Land Cruisers also have what he is looking to add. I believe it is a hydraulic based system, not air.

If you want to add it to a 4Runner, the best way to install (I think) involves selling the 4Runner and spending a couple grand extra and getting a similar year LX.

I think what you are wanting is an airbag setup in combination with the bilstein 5100's. Im sure they don't make a bolt on system for the 4runner, so you would need a fabricated setup/brackets to mount the bags. Plus the compressor, tank, valves wiring etc. You will need to do a bit of research or go to a custom 4x4 , airbag, or hydraulic shop. If this in fact what you are looking for.

checkout whorerunner on instagram. He's got a bagged rear, not sure how. It's super bro.

Edit: Not the same as whorerunner on here, sorry for tagging you lol

Yeah, this is what I was looking for. It does not appear that there is anything close to a finished system that is sold as aftermarket. As you said, the closest that there appears to be is an amalgamation of parts that may/may not work.

Now, the reason? Initially, I was concerned about two things: MPG and garage door height. I was concerned that after adding the lift and roof rack, I would be too tall to get in the garage. After some measuring, I think I'll be fine there. I wanted a suspension system that would allow my to lower the ride height when going into the garage and then lift when I'm back out on the trails. Now, it's more of a curiosity to see about saving some MPG's. Hearing that this might need to go to a custom 4x4 shop, I think I can afford to pay the extra gas.

I appreciate all of your feedback, guys!