What sort of price is the Gravely 34?
It weighs 725 lbs, man that's heavy, definitely would need to do the tire upgrade! Almost twice the weight of the husky!
Not sure if Porcupine requires a catcher, but the gravely doesn't appear to have a rear mount bagger, it would be an accelerator. Only problem I can see with that is this makes it so wide, kind of defeating the purpose of having a narrow Z, ie trying to fit through a tree/garden bed while mowing or just a couple fruit trees planted together etc.
Im now trying to imagine the husky with those wide tires fitted, providing it doesn't make the machine too much wider for gates, then it would be an excellent mod!! could make the difference between mowing after some rain or not for the risk of rutting.