I have also 1031A. Mine are -2 on tweeter and flat on the rest. The hiss is not normal thing. Mine are also very quiet. I suggest you try the -2 or even -4 on the tweeter, it depends all on your room acoustics. I just got the huge Behringer Truth subwoofer to test with my Genelecs and it's great. Don't think if buying the 1031A you won't need it. It's a big difference. 1031A are not so deep or full of bass, they are deeper than the ones you have already but still not enough, except if you mount them into the wall.
...my 2 cents.
Purusha