JD101b

Recently, business has me traveling through rural areas with choppy roads and huge snowfall amounts. I've been thinking about lifting my new-to-me GL550 and fitting some bigger tires along with some auxiliary lamps. I'm trying to figure out my options here and they seem to be the following:

-Fit larger tires on my otherwise stock truck: What are the largest tires I can fit with the stock suspension and wheels?
-Keep the airbags while figuring out how to keep them locked in the raised setting. Is there a way to do this? Or, are there "bigger" airbags that I can fit which gives the truck a taller ride in "normal" height?
-Ditch the airbags and fit springs that would give a 2-3" higher-than-stock ride. The air springs/adjustable dampers do give a great ride, but is this the only realistic option to get a taller ride height? Is there a way to keep the stock adjustable shocks if I go this route?

Also, if I do mount lights up front, what are my options in terms of mounting points and wiring?

Thank you!

mtm

Check out this OBD plug/module. It's primarily for lowering, but can raise as well.

JD101b

I've seen those before, but it is safe to run the vehicle at highway speeds with the suspension in a raised setting?

The truck has a wider track than a GL450, and I'm thinking about fitting modest spacers, but is the suspension itself affected in any way?

mtm

I guess it's as safe as any other suspension lift. Raised center of gravity, altered suspension geometry, increased driveshaft angles - but whether or not 2-3 inches that you want to lift will make a significant difference, I don't know.