I would reach out to Odyssey customer service and verify that the aux terminals on that specific battery are suitable for extremely high load. Some marine batteries are meant for trolling motors, etc. with low loads. A high current draw on those terminals might damage the battery internally.
The only mod is the plastic tray that comes with the battery to raise it up slightly. No modification to the cables needed.
As a side note, the Interstate MTZ-34R is a good and less expensive alternative to the 34R-PC1500. The MTZ is currently in my LX450 after I drained my PC1500 flat on the...