I am getting 2 new polk mains and i have a rca 500 watt, 5 channel receiver that I got last year. I use it for 95%music and 5% movies or less. I also have the 4 bookshelfs and 1 center that came with the receiver and a sub that sux too. The system stinks. I am upgrading gradually. I really dont have the money to upgrade the receiver, unless I can get a good receiver(onkyo?) for around 250 used. The polks will make a nice upgrade. Should I wait and be able to spend more money on a receiver or get a eq or amp now? If so, which? What significance does an amp or eq really make? What are their main roles in 2 channel audio and/or HT? Iuse mine for 2 channel. Thanks a lot.