When my Xantrex 2500w inverter failed a few years back, I had it replaced by a Xantrex 3000w. The newer Xantrex inverters came in 2000w and 3000w sizes (no 2500w), so I elected to get the 3000w. No changes to the coach wiring were made to accommodate the change from 2500w to 3000w.
The firm I used in Tucson, AZ dealt with and repaired (if repairable) both Magnum and Xantrex inverters. Because the battery charging internals in the inverter had failed and were not repairable, the firm recommended I replace the Xantrex with a Xantrex. If I remember correctly, the firm preferred Xantrex over Magnum, but would, of course, follow my desire for either brand.
Those inverters are very heavy. I helped the technician get out the old inverter and install the new one. We used a small golf cart tire-jack to hold the inverter up into place while unbolting the old inverter, and remodeling the mounting bracket and bolting into place the new inverter. I don't know how the technician could have done the replacement without at least a second person to help handle the weight in the confined workspace where the inverter sits.
The technicians also had to install new wiring for a new battery temperature sensor, a new AGS module, and a new remote panel.