I don't understand "the mark II version" either... the Tituses were
sold in the XS version first, then the 202, then the current ES. I hope I have
that right and that someone will correct me if not. Perhaps the one you have
is the 202.
I have the ES version. From what I have read, the XS version had tweeter
reliability problems, the 202 corrected that and sounded better, and the third
is the best. I haven't heard the others but I can certainly vouch for the third. It
is a very pleasant, rich and involving speaker. Getting the best bass out of it
requires careful placement and room treatment helps, but it is no worse than
many small speakers I know, bass-wise. If you read reviews and owner
comments on the larger Triangles you will find that people talk about their
bass in quite complimentary terms. The Comète ES for example, the next step
up, is said to have much better bass than the Titus, but it sacrifices some
speed with its larger mid-woofer.
I have listened to my Tituses with a NAD C320BEE and I did not like the sound
much. I prefer higher-quality amplification, perhaps Creek or SimAudio,
although my antique HK930 receiver did a creditable job. The problem was
just as you say, a thin-sounding midrange, as well as some distortion of the
soundstage. At present I am using a very good-sounding Chinese-made SS
integrated, but I have heard the Titus ES with tubes and that's what I hope to
get soon, because the midrange was really nice.
I realize this is not a really direct answer to your question but I hope it helps.