I suffered the same problem as you this year. I95 bent my rear axel on my 2011 keystone Passport 2910BH. I knew if I just replaced the axel I would be in the same position again as we travel long distances. Trailer weighed in at 6900 lbs. loaded on the scale. GVWR is 7200 lbs. Axels were 3500 lbs. with 1750 springs and 14 in. wheels and tires. I Upgraded to 5200 lb. axels, 2500 lb. springs , and 15 in. wheels with load range D tires. As stated above gained about an inch in ride height and it tows much better. I also put Dexter heavy shackles and wet bolt kit on as well. You also get larger breaks with the axel upgrade so they don't have to work as hard either. Cost About $2,000 to do the whole thing. Me and a buddy did the swap in a couple of hours. Not a hard job at all.