According to the current brochure only the MBS has the two point system as a FR option. The four point system is offered as an option on the E-450 chassis and Chevy. But in case that has changed, or you are looking at aftermarket systems, here is my experience:
I had the optional rear stabilizer jacks on our M-B "W". They were not worth the money IMHO. The two major issues were:
1. They were located to far forward from the rear bumper. This left several feet of the rear overhang unsupported....like the shower. More on that in a minute...
2. They were located to far inward towards the coach center line. This caused side to side sway.
Because of the jacks location I could hop in the shower and have the coach "rocking and rolling" just about as much with the rear stabilizers deployed as without deploying them.
In fairness since you have a Ford E-450 those issues may not apply at all due to a totally different chassis and jack location layout.
My question is why only get rear stabilizers when you can get a four point
leveling system? Our GTS has the four point Bigfoot leveling system as a FR option and it works great! I'll never have another motor home without a four point leveling system.
Your results may vary...But I'd check them out before buying them to see if you have the same issues I did...