Got everything buttoned back up today, while the wife was doing all the pre-Easter cooking. There are still some things I want to do to further improve the sound deadening, but I needed to get the tractor put back together since it's been torn apart for a week and a half, and need to do some work with it next week.
Soundproofing seemed to help some, though probably not quite as much as I had hoped. I can still hear the hydro whine, though it seems quite a bit more muted than it was before. Engine noise is muted quite a bit more.
It was a pretty involved project. Was it worth it? I guess every little bit helps, though for the amount of work & time in pulling everything apart, I would have preferred even more sound control. I am glad I did it because it did help with the overall noise issues, and the sound that does get in, get's absorbed more quickly, instead of bouncing around as much.
I really think installing a rubber backed outdoor carpet on the seat pan area would do wonders, but right now, I'm not quite ready to do that, with the seat frame and all the levers, it would be a difficult project. However, I think I am going to add something to the rear panel with the tool box in it, because I think that will help a ton with sound absorption. I also am close to pulling the trigger on treating the cab side of the pillar covers, but first I may try adding some self adhesive foam to the back side and/or butyl sound deadener - I did stuff the pillars full of foam, but the plastic fasteners don't hold the covers tight enough to keep them from sounding "tinny".
Also got the new stereo installed. I used foam spacers to mount the speakers since I could get those cut quickly. Doesn't look quite as good as Waxman's nice plastic spacers, but that's something I can do when I have more time. For now, the foam spacers are working nicely. The sound is impressive - much, much better than I was expecting, and apparently, these speakers need about 10 hours of play time to "break in".
I went with an Alpine mech-less AM/FM Bluetooth unit with sync that I can make/receive calls through the stereo (note the mic mounted on the headliner) and listen to music off my iPhone via bluetooth or USB cable. Pretty slick setup. I installed JL Audio Evolution C2-400x 4" coax speakers. I am very, very impressed with the stereo system, and am very glad I did this install, and think the soundproofing work helped quite a bit to create a decent listening experience. I spent quite a bit of time driving around at 2000 -2500 rpms to get a feel for how the stereo would sound with the engine running at working rpms and the hydro whine going up the hills, and can say that I am impressed. Glad to be rid of the earphones.
I also installed a ski boat rear view mirror because I didn't like the blind spot between the factory mirrors.