I don't think the insulation is going to cause any problems. A 1" thick panel isn't going to absorb any low bass and that's pretty much all that comes out of the port.

I don't remember how much spacing is required, and I'm not a good one to ask because I like my speakers far away from the wall...

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8