You can find my take on the Spendor SP2/3R2 against the Harbeth M30.2 Anniversary here: https://forum.audiogon.com/posts/2700741
I have found the Spendor Classic 100 (same series as the 3/1 you are inquiring about) to sound even more colorful than my SP2/3R2. As a side note, I wouldn't call the 3/1, M30.2 etc. "large"; 2/3 are "quite large" (but my brother called them "huge", to my amusement as I was also having a pair of Martin Logan Impression 11A at that time, so I guess it depends on one's point of reference); Classic 100 and M40.x are "LARGE"!