will19 it sounds like you aren't breaking any tenant laws in your building with your weight training. I think you should just let it go. You've talked to your manager about it and are in the clear as far as the noise goes from your weight training during normal waking hours. Its one of the downfalls of living on the top floors of apartment buildings. I have lived on every floor of apartment buildings and there is no one "perfect floor." It's mostly who your neighbors are. If they are jerks who live below or above you, nothing you can do except report them to your building manager and hope for the best outcome.

Your neighbors are just nitpicky people. You can't change that about them unfortunately. You are legally allowed to weight lift in your apartment during waking hours. They are just jerks.