Am fixing up an MC2505 soon with intention of comparing to my sansui gear...
That is meant to be one of the warmer Mcintosh so I thought it might be a good starting point.
McIntosh's are not warm, if they are, there's something wrong with them, they are powerful, punchy, detailed and accurate sounding, I have heard a LOT of McIntosh gear, and "warm" is not an adjective I'd use.
The MC2505/250 was the first solid state power amp they made, and the design of that amp was so well engineered it was some time before they replaced it...MC2015/2100 fits into the same boat...
I completely restored a MC250 (Same amp is the 2505 but without the meters), and i unplugged my G22000 pre-amp from the power-amp section, plugged the MC250 in, and it seriously, despite being a little less than half the power of the Sansui power-amp, Blew the Sansui out of the water....utterly and completely.
However, generally speaking, you need to go to McIntosh separates like a C28,29,30,32,33 pre-amp and at least a MC2505 maybe a MC2205, and that alone will be about 3 times the amount of money you want to spend...
My C33 pre coupled with the MC2205 is pretty hard to beat driving the JBL L7's......but then there's there's my main system, not exactly "bang for buck" but who cares when you're listening to it!!
The lower end MA1700/1900 etc are not anything that special, and I would personally take a G9000 or similar over something like that....An AU999 with my mod's would blow one of those out of the water, easily...