We haven't confirmed this yet but I would think that a 31" tire would fit, maybe a 32" tire.

Will your kit work with the 2 axle air suspension? I am not a fan of the front bumper so I would prefer keeping it stock looking what would the largest tire usable with air suspension in the extended position?

Someone correct me if im wrong but i dont think you can go bigger than 28"s. i have 28inch diameter tire and its got no room for play it sits around 10mm from the front bumper on full lock inward, so take that as you will.
I do not have air suspension though.

The kit does work with air suspension in the rear so no worries there!

In regards to tire size, there are a few variables that will come into play.

bimfest, pending on what offset your rims are that space at full lock can be possible be improved.

Guys have told us that a 31" tire has been fit without issue (not sure on offset). Judging by what we've experienced with 33's, I would think that with the right offset, 31's would have minimal and tolerable rubbing.

If you were looking to keep a stock looking rim, spacers could help push the offset out and possibly allow a bigger tire.

Hope this helps.

I was concerned with the system working with the 2 Axle Air suspension and the largest tires one could run if the suspension was in the extended position. I have an aftermarket air management system that allows me to adjust the ride height on the fly.

hmmm, we've only run the system on stock air suspension so I can't say for sure if the lift would work with your aftermarket setup.

Its a factory system, ie the front and rear struts/airbags are the factory parts, I just have an aftermarket management system that allows me to choose my ride height. The problem is, you have never said if it will work with both FRONT and REAR air suspension, that was found on the 4.6's and 4.8 E53 X5's. That's all I would like to know.

Thank you for clarifying. We haven't confirmed fitment on X5's with air suspension in the front so that's something I'll have to look into for you.

Lift kits are selling quicker than we anticipated so there aren't many sets left. Order yours today!