Robert - can you say if adding in that Toro version that hangs from the unit would or wouldn't void the warranty?
The warranty can't be "voided" as it's a binding legal document between you and Honda. Adding any aftermarket part/accessory or modifying the mower does NOT void the warranty.
That said, the warranty only covers defects in manufacturing and workmanship. The warranty does NOT cover problems caused by aftermarket parts/accessories or modifications to the mower. Example: You install an aftermarket striping kit and it requires drilling into the handlebars. The holes you drilled start to rust, and the handlebar breaks. Repairs would NOT be covered under warranty. Further, let's say you install a striping kit and the recoil starter fails for some reason, but it's obvious it had nothing to do with the striping kit. If the failed starter was found to have a factory defect, it would be repaired under warranty.