That's a great looking Suburban, I am partial to GMC Suburbans myself, they grow on you over time. Have you considered installing
3:55 gears to replace the 4:11's that you have now? It will get you more speed and a quieter ride too. This allows you to keep the original transmission and torque tube rear end. If you like doing your own work and have the tools and the space to do it, there is lot's of information to assist you. If you don't like doing this kind of work, I am sure that there is someone in your area that can. There is a guy in Arizona that sells the kit too, not just Patricks, although Patricks can answer many of the questions that you may have regarding installation.
Remember for every action there is a reaction, so when you change the tire diameter you could be affecting your RPM'S too. These trucks were designed around a 31" high tire, installing a shorter tire will result in higher RPM'S. Good luck! ......g