Your thinking correct
yes, Rubi does have locking differential, this is great for rock climbing.
Rubi is the top of line, meaning it is ready to go off road at trail rate of 10! There is off road trail rating from 1 which any vehicle can go, up to 10 where only serious built vehicle that is designed for this rating can go. Wrangler Sport can go up to 7 I think, that is without modification. No average vehicle can go above 3. Trail rating of 5 or higher, which mean expect some damages (Already had happened to me) RickL66, correct me if I am wrong.
Rubicon got better suspension than Sport.
If you got extra cash, Wrangler sport would be cheaper, and you can lift em, replace with 33 inch tires, and if you want go rock climbing, then locking differential can be added; all for less than what Rubicon would cost you.
Wrangler Sport or higher has Skid plates, which protects whatever is underneath the Wrangler like muffler, tranny, xfer case, etc from any elements. I have Skid plate and man! some of them are severely scratched from whatever (I had no idea what) though the offroading, if not for the skid plate, I would cry.
If you know how to stick, then go for it, it is far better with stick than automatic.
I was hoping that I would be able to build my Wrangler sport into Rubicon style in near future. I said Wrangler Sport because I do own trusty Cherokee Sport too.
Finally do not bother with X or SE, they are not as great as Sport, and many of them has 4 cylinders. Mine is true four point zero litre, 6 cylinder, the best motor!
is there a major difference between sport and rubi? like locking diff.?
It also snowed this morning to my surprise! 
We are gonna have snow, rain and high winds for today....rather stormy. Also, there is going to be flooding due to heavy rains.
