I'm (sort of) with @holmz . For $1k, I think you can make some sonic changes by replacing something, but it may be the sort of thing you like at first but then later realize it doesn't really allow you to enjoy the system more.
You did not mention your room. I would think real hard about the room, speaker placement, setup, etc. and fiddle with that. You may find the need to spend some or most of that budget on some treatments or other things relating to the setup, and if there is improvement to be made in terms of setup, it will vastly outstrip what you can achieve by dropping $1k on equipment given what you already have.