The EZ-Steer and T2 that you already have will work with either the EZ-Guide+ or the EZ-Guide 500. However, if you use it with the EZ-Guide+ you have to have firmware version 3.something and if you use it with the EZ-Guide 500 you have to have firmware version 4.something. I can't remember if it's 3.11 and 4.11 or what. Anyways both the EZ-Steer motor and the T2 box loaded with firmware version 3.something are required for connecting to the MojoRTK unit if you're going the EZ-Steer route. That's what we do. Some people have tractors like a Cat or a John Deere that already have integrated hydraulic steering and the Mojo can talk to those so you wouldn't need the EZ-Steer in that situation.

In answer to your question, the Mojo setup that you would buy for 13,000 dollars would need to be supplemented with the EZ-Steer motor and T2 box that you already have. There would be no reason to have the EZ-Guide+ or EZ-Guide 500 in the same tractor as the MojoRTK unit because the MojoRTK unit talks directly to the T2 box which sends the signal to the EZ-Steer motor.

The MojoRTK unit does have a screen which has a small lightbar like display on it. It will drive you crazy because it works the exact opposite way of the EZ-Guide+ which you appear to be familiar with. If the dots are to the right of center on the EZ-Guide+, you drive to the right to center it. On the MojoRTK if the bar is to the right of center you drive to the left. The lightbar feature would be all but useless for steering the tractor manually. It shows either three or four (I can't remember right now) bars to each side. If the middle bar is solid you are 0" to 2" offline. If the solid part moves one bar to the right that means you are 2" to 4" offline. The second bar would be 4" to 6" and the third bar would be 6" to 8". I'm not sure if there is a 4th bar but you get the idea. Basically it means that if you are more than 10" off you won't see any solid bars so you wouldn't be able to tell where you are and driving manually you would frequently get 10" off.

The redeeming factor of the lightbar is that directly below the lighbar but on the same screen is a visual indication of the AB line (Leica calls them waylines) that you want to follow. This gives you an indication of the angle at which you are approaching the line as well as an idea of what side you are on if you are more than 10" off. Still, it's designed for the auto-steer to do the work for you rather than for you to be staring at it driving manually all day so it's not a big issue. If you did have the idea that you were going to be looking at it very much it would be important that you find some way to mount it so that you can see it all the time while looking ahead. Fortunately our JD 4840 has the radio mounted perfectly in the center of the tractor so all you have to do is look slightly up to see the MojoRTK console. In some tractors I know the radio is on either side in front of you or even clear off to your right so if you feel that you will be looking at it often you may want to consider the implications of having to look to wherever your current radio is mounted.

If you go to http://www.mojortk.com and select your country you will see "Education Center" on the left side. This is a good site to find lots of information about the MojoRTK unit before you buy it. The best one to start with would be the "mojoRTK User Manual Ver. 3" under "MojoRTK User Guides". Download this and read it and you'll have some sort of an idea of what you're getting yourself into before you buy it.

I must say I was dubious about the product after we first got it but Leica appears to be putting a lot of work into it and it has improved significantly in just the short 6 months that we've owned it due to regular software updates and great over the phone tech support.

At the same time, it is important that you do what is best for your situation. As you can tell from what I've explained, while there are many positives (increased accuracy, no subscription fee, don't have to wait for the Omnistar signal to converge), there are many negatives as well (having to carry the base station around or figure out a permanent high mounting point, probably a steeper learning curve, not having a large easily viewable lightbar if that's an issue for you). My only real intent of this was that you probably shouldn't make a decision to go with either the MojoRTK unit or the Omnistar option based only on price because once you figure what the subscription is costing you they are really very close to one another. You just have to decide what is going to be most useful for you in the long run and put your money there.