they’re not gonna shut up no matter what you do. It’s not like the guy is going to stop fucking his g/f just because the neighbor is complaining. Talk to the landlord and see if he’ll reimburse you the cost of that acoustical stuff. Then next time they’re making noise, record it, and play it back at them through your stereo. Or throw a nyspeed party and we can all cheer through the walls and yell out positions they should try.