Bump stops will not prevent tire rub, unless you go with some very rigid aftermarket units. You should buy the shocks that you are unsure about and let us know if they work. That will greatly help anyone looking for this specific answer in the future.
You will gain nothing from running the 5165 model. Your tire will most likely rub because of the rear axle articulation. The 5100 are robust enough to handle any type of driving you will do with your r50. Stick with the 5100 model and save yourself a bit of money for other mods.