Generally, the first two places I look are through
Stereophile's archives (they have Primus 360
measurements) and then through
Sound Stage Network.
I must point out that access to these extensive measurements is useless without a strong understanding of how to correlate actual measurements to listeners preference otherwise you will simply be looking at various graphs with no true understanding of what they mean in terms of perception. If you are truly interested in gaining an understanding of what these measurements mean I suggest you start out by reading the following articles.
Listening Tests-Turning Opinion into Fact. Toole, Floyd. JAES Volume 30 Issue 6 pp. 431-445; June 1982
Subjective Measurements of Loudspeaker Sound Quality and Listener Performance. Toole, Floyd. JAES Volume 33 Issue 1/2 pp. 2-32; February 1985.
Loudspeaker Measurements and Their Relationship to Listener Preferences: Part 1. Toole, Floyd. JAES Volume 34 Issue 4 pp. 227-235; April 1986.
Loudspeaker Measurements and Their Relationship to Listener Preferences: Part 2. Toole, Floyd. JAES Volume 34 Issue 5 pp. 323-348; May 1986.
The Modification of Timbre by Resonances: Perception and Measurement. Toole, Floyd. JAES Volume 36 Issue 3 pp. 122-142; March 1988.