I had a pair of Apogee Centaurs which I think the Slant 6's would be similar to. I'd second the ModWright. At the time the best sound I got out of my Apogees was with a ARC 100.2 over some Levinsons and Krell's I tried at the time which were too analytical on those speakers. The 100.2 is a great amp but not sure if the DSi200 has the magic the 100.2 has. Personally the newer ARC SS amps don't do it for me. Between that ARC and the ModWright on your speakers I'd go with the ModWright if you can't hear them first.
Consideration of amp change
Been thinking about a possible change of my integrated amp (current Classe CAP 151) and have under consideration the ARC DSi200 and or Sim Audio 600i. The front end is ARC CD 3 Mk 2 with Apogee Slant 6 speakers. I listen to rock, soft rock, jazz, new age and blues. I'm hoping to expand the sound staging (without being analitical) and want to try to expand the micro details from the music I listen to (see my system for all the details). My biggest draw back is that I don't have access to hear these pieces of equipment for comparisons though so I have to rely on educated opinions. I DO NOT WANT to go separates, (so please don't suggest any of that). Suggestions are welcome and appreciated and I'm working with in budget limitations with a top of $3K-$3.5K