I have the 4367, as well as experience eith other horns.
The sensitivity rating usually is: 1000hz test tone measure at 1 meter on axial. It tells you absolutely nothing about the actual sound coming out from the speakers. whether its coming out ok, or harsh.
Compression drivers need as much CLEAN power as possible to sound the best. Thats why JBL rates 4367 and other of their monitors 300w amplification (its on the manual). The tone/sound is completely different when it sings at its 100%. Where the clean power coming from is up to you, and of course personal taste and music types dictate the amp choice, but if you are push ur JBL w 10w of whatever, at least borrow someone good 100-300w amp and see the difference.