I have owned a GK 212 with the RB1001 for about 2 months and have 6 hours on them. I went to a local music store today and could not pass up on a deal for a Mesa 112 for 499.00 icl tax!!! This was 7 months old and looked brand new. I now have the GK Neo 212 with the Mesa Subway 112 with the RB1001. WOW, the sound is awesome. the question I now have would be , do I get a better deep thump adding a GK Neo 115, Mesa Subway 115, and selling the Gk212 (which I just listed for 600 on FB) or do I keep this stack and just enjoy what I needed up putting together? Opinions, experience etc etc appreciated. Thank you.