Personally, I think the weakest link in your system is your preamp. Don't get me wrong, I have nothing against Rogue gear, and own the 88 amp myself. But I was not much impressed with the 66 preamp.
If you like the tube warmth, I would recommend trying an Audible Illusions preamp with your setup. If you want something more toneally neutral with PRAT, can't go wrong with a BAT VK-30 (I can say from personal experience that Rogue 88 and BAT VK-30 are a great synergistic match).
Used, either preamp should be well within your budget for cable experiments =).
If you like the tube warmth, I would recommend trying an Audible Illusions preamp with your setup. If you want something more toneally neutral with PRAT, can't go wrong with a BAT VK-30 (I can say from personal experience that Rogue 88 and BAT VK-30 are a great synergistic match).
Used, either preamp should be well within your budget for cable experiments =).