Hi I am looking to upgrade my existing (20 year old) amplifier and wondering whether this would be a significant upgrade. Current model is a Sony STR-D311 Receiver. I can't find much info online (I guess because it's so old) but this is the instruction manual that has some specs - http://www.docs.sony.com/release/STRD311.PDF I am looking at the £200 - £300 range, and was considering the Marantz PM6004 - http://www.amazon.co.uk/gp/product/...&pf_rd_t=3201&pf_rd_p=466496393&pf_rd_i=typ01 But I'm open to other suggestions in that price bracket. I use it for DJing in a fairly small basement room - so especially interested in good bass reproduction. I have 2 x active monitors, 2 x floor standing speakers and 2 x bookshelf speakers. So, a few questions I'd appreciate some guidance with: 1. Would this be a significant upgrade to be worth the money? 2. Should I consider getting a DAC too, as I mostly play digital files (MP3s)? 3. Is it worth adding a subwoofer? Any guidance or advice would be much appreciated.