I just put (well finishing the install today) a 9.5XPS in a Trail Tailor hidden winch mount on my 2015 LX570. I also am an instructor for 7P Overland and Overland Expo. I teach a lot of winching classes. That's not to say I am expert, far from it, just giving you my advice and some light background.
While you will hear a 1.5GVWR number thrown around a lot it really depends on the type of wheeling you do, the terrain, etc. Most winch scenarios do not result in a 100% vehicle weight load on the winch, this is because of those awesome things called wheels and tires. So, really what you are looking at is rolling weight. This is why you see strong men pull trucks and teams of people pull airplanes. Think of your winch in the same manner...what you need to take into consideration is weight, rolling resistance, etc. If your truck is sunk in 3 feet of mud, that's not just vehicle weight and rolling resistance, but...now you are factoring in suction strength of the mud. Likewise, if you are on a rocky hill and winching up that hill, it's not a 100% vehicle load on the winch, because part of the weight of the vehicle is still being born by the tires, realistically the only time you would have 100% vehicle winch is on a pure vertical pull. So, having said all of that...there is no one answer.
In addition, having a recovery ring or a snatch block (or two) allows you to create a pulley system and increase the effective pulling power of your winch through mechanical advantage. This also decreases the workload of your winch. I generally always use a recovery ring to a hard point and then loop back to the vehicle. This gives me a theoretical 2:1 mechanical advantage and decreases the force on the winch by half - albeit in practice it's probably a little less than 50% after you take into consideration resistance, etc.
So, my recommendation would be that unless you are planning on doing vertical pulls or deep mud pulls, a 9.5XPS should be fine. Add a recovery ring, soft shackle, and tree strap and you are setting yourself up for success. Add in another recovery ring and there isn't anything you wouldn't be ready for.
Factor this in as well, a recovery ring, soft shackle, and a tree strap will be less than the difference between the M12000S and the 9.5XPS.
Link for reference and video embedded video on Recovery Ring use:
7P Overland has developed a great recovery system that can replace heavy, awkward, and often dangerous pulleys and snatch blocks. The 7P Overland Recovery Ring system (consisting of a lightweight ring and soft shackle) is a simple design optimized for today's synthetic winch lines. Designed to...
www.farageprecision.com
- Mark