I have an 08 160Z with the 25hp kohler and 60" X-Factor deck. I now have 1300+ hours on it and it has been relatively trouble free. It cuts great and leaves a very crisp smooth finish cut in our northern tall fescue grass. I do have a few things you can work on improving.
1. Discharge. For what ever reason this mower does not discharge way out the side. It kind of directs the grass out and down. This is not good on those thick lush spring lawns. It leaves heavy rows of discharged clippings requiring a second pass at a higher height to clean it up. If it threw the grass straight out instead of directing it down and out that would solve that issue. I do not run the chute.
2. It is not as easy on the turf when you turn as some other mowers are. It wants to drag one rear tire depending on what direction you turn. It even does it on asphalt. For example last year I demoed a much heavier john deere Z920a 60" and that mower would turn so easy it would not tear up a lawn. I thought being 200+ pounds heavier it would be worse so I was surprised when I got to use it how easily it turned!
3. Please put grease fittings back! I absolutely hate not having grease fittings! I just had to replace the front castor bearings this spring. I am sorry but I am NOT going to disassemble them every year to repack them when all that is required is a simple grease fitting!
4. Please stop with the terrible cheap seats on the lower end models like our 34Z and 160Z. Im not saying you have to put the high dollar suspension seats on the lower end models but the seats you use fall apart WAY to easily. Our 1998 lazer z hp has over 2500 hours on it and the seat is just now starting to have issues. We have never had a gravely seat last more than 800 hours before it starts falling apart.
We do like our gravely mowers but may be switching on our next purchase if some issues are not addressed.
2013 Gravely 460Z 29EFI
2011 Gravely 36GR
2008 Gravely 160Z
2004 Gravely 34Z
1998 Lazer Z HP 48 (old faithful)