I am not going to talk you out of it, but let me give you a bit of some facts that you have to be careful with.
1. The RS40 is rated at 1300. However, that is absolute best case...shortest throw, high lamp, brand new lamp, iris fully open, and still there is some variation.
2. The RS2 was rated at 700, same setup. Now while it is a large number difference, the RS2 lamp dims generally slower over time, and, what would appear to be a nearly 2x increase, to the human eye will not appear as such. Yes, the RS40 is brighter. But I wanted to make sure you understand the reality of the difference.
3. The contrast on the RS40 is 50000:1, vs. 30000:1 for the RS2. Again, depends on setup. The RS40 only does potentially 50000:1 at the EXACT OPPOSITE settings as above. You won't get 1300 and 50000:1. Moreover, here is how contrast works. It is white level over black level. Say the measured white level of the RS2 and RS40 was the same, say 100 for a random number. To go from 30000:1 to 50000:1 would change the black level from .0033 to .0002. Your eye will never see that in reality, especially when actually watching a movie since it cannot possibly change that fast with the content.
Again, I am not trying to talking you out of it. But, really the differences in the 2 should be looked at in other ways as well. The RS40 has a fairly accurate color setting unlike the RS2. It is 3D (take it or leave it), the panels are generally better and have better uniformity, no bright corner potential. The lens is a bit better made, including the shift and such.
So you really have to look at it from a whole, because if you merely are looking for light output and contrast, you may not be as happy as you hope, if you are thinking about the numbers as most do.
My 2 cents.