JA Pulsars vs Harbeth 30.2

Both Harbeth 30.2 and JA Pulsars are excellent speakers but they’re not going for the same buyer profile IMO. 30.2 is more of a monitor speaker and has a distinct sound. I would never advise anyone to buy the 30.2 without listening. You will either hate it or fall in love with it. 
 

Pulsars are more traditional in the sense that they will sound more similar, but overall much better, than your existing speakers. 
 

Having said that, given your room size why are you looking at bookshelves? You can easily accommodate floorstanders in that room. 

One more thing, Harbeths will never sound thin. Whether you like them or not, one thing they’re not is thin sounding. 

Harbeths need a beefy amp to drive them. If they sound thin or soft, usually because the amp is not powerful enough to drive them. But yes compared to Joseph Audio or Focal etc, they’re not treble-focused. 

Definitely go for the 30.2 if you’re planning to audition. Harbeth has tuned the 30.2 to be a bit more open and airy (better treble) compared to the 30.1. If you feed it with good amplification it will not be ‘soft’ at all. What it won’t do is to throw the detail in your face. You will notice that all the detail in your music is still there, it just doesn’t ‘prioritize’ higher frequencies compared to the rest. This makes for an excellent speaker for long, fatigue free sessions.