If you can swing the price of the ticket, the RM40jr is your ride. I think there may be a couple pair of the Cherry left at $2999.
I just picked up my pair for my HT, and anyone who misses this deal is missing a huge AUDIO bargain.
And they will play LOUD, Distortion FREE, and with BASS that will Rock your World.
Now if that cannot be "wedged" into your room, the RM2 will certainly provide the lowest bass response, but the extra NeoPanel of the RM30 makes it a slightly "cleaner" speaker at higher levels.
The bass of any speaker VMPS or not will only be as good as your room will allow and support.
With the RM40 you will be in the low 20's
With the RM2 in the low 20's
With the RM30 in the low 30's
I think the RM1 is also in the low 30's but as Brian said, the bass distortion in the RM30 would be less.