ive got one running right now in a .75 cu box in my truck and it sounds like a 10 very very clean sound i love it cant wait till i have the power to push the others...
I've just installed 7 re8's in my truck, haven't had time to really check them out for SQ. Ported I will say they get stupid loud for how cheap of a driver they are though.
Here is a link to a review of alot of 8's (Loyd's Great 8 challenge). It looks like the re's didn't do great for SQ: