Ok, no anguished cries, but before you do anything to the Disco 2, a fairly capable vehicle already in its stock set-up, the first question to be answered is "Why?"
Why do you feel the need to remove what is essentially a good suspension system and replace it with steel springs? Do you have the kit to sort out the SLABS ECU after you've change to steel?
The self levelling suspension is also quite good when off roading, and you also have the facility to raise the rear suspension about an inch or so from the dashboard if it's needed. It's also easy to understand as long as you treat each piece as a distinct part and don't try to over-analyse the electronics or reasons for any failure. The only real advantage of steel springs is that it's easier to see a broken one.
There are "lift blocks" available for the Disco 2 with air springs, but no amount of lifting is going to increase the ground clearance under the axles and diffs, all it might improve is the entry and exit angles at the front and back of the vehicle. You should also be aware that lengthening the springs by whatever method you decide will probably require that you change the shock absorbers too since they will be operating "off centre" with an unequal "extend and compress" distances.
The Active Cornering Enhancement (ACE) is also a useful system, even when off-roading. It is a totally separate system, independant of the SLS. It does have its problems, mainly leaking pipes, largely due to corrosion. Some members have modified their Discos to use hydraulic hoses instead of the steel pipes which seems to be quite successful.
In some cases, there might not be any need to replace the ARBs, there is a mod somewhere which calls for the ACE active anti-roll bars to be drained of oil and filled with grease to lock them solid, but you're still going to have to remove the pump and switch off the system at the ECU.
All-in-all I would advise you to get to love the Disco 2, including its extras before you start converting it into another 110.
You might want to take a look at the post by
@300bhp/ton on this page on the forum where you should find a load of useful information:-
https://www.landyzone.co.uk/land-rover/lifting-a-d2-properly.300573/
Edit
After giving it some thought, access to a compatible code reader is going to be needed whether you go for steel springs to switch off the air system or using lift block but in this case, to re-calibrate the height to include the thickness of the blocks otherwise the SLABS ECU will just deflate the system to bring the outputs from the ride height sensors back into within the original limits.
