My buddy is looking to upgrade and wants to sell me his speakers and reciever. He wants $500 for: Onkyo TX-SV727 reciever JBL LXE770 front speakers JBL J520M rear speakers JBL SC305 center channel speaker The system looks like it's in good condition, and sounds good as far as I can tell. I'm no expert though. He says he bought it all in 98'-99'. Is this a decent deal? I know I will still need to buy a subwoofer.