I've been in friends' cars with dumps, and it's not that bad inside the car. Outside's a different story.
You don't HAVE to dump to the atmosphere just because you have a divorced WG. You can always plumb it back into the exhaust, as long as you do it right, but you will lose a few HP and a little bit of response, but it is a lot quieter.
The 2871r and the 3071r both can be had in a T2 ot T3 configuration, so it really is up to you to decide, how much power do you want, what your goal for your car is, etc.