I have narrowed my search for a 2007 Expedition EL to 2 vehicles, one with the Load Leveling System and one without. Both have the heavy duty tow package and I will be hauling our 5,500 lb, 31' Forest River Surveyor SV-294 travel trailer. We will be using the EL for more than just camping. Is there anything that should make me decide one way or the other concerning the LLS? I've read that they are expensive to repair. Can they be converted to coil suspension? Are there lift kits available for it if I need it for towing? Our Forest River road low to the ground and I had to put a 3 inch lift kit on it in order back it up our inclined driveway without scraping the bottom. This was with our Ford E350 Super Duty, which road pretty high off the ground. Any suggestions? Thanks.