Starting with the API emulations , those are great emus , light on cpu , superbe layout (even if the old one "frequencies displayed" style was a little more fast to tweak )and great sounding .
You guyz must know that it introduce saturation / distortion with a fair amount of compression when pushed , also those curves (eq off ) are not linear frequency wise :
The EQ PA has the most bass heavy curves , distortion is pleasing , compression responsive .... to be used when you need meat , body or calm done highs side on a material ...
The EQ PB is like the PA but less violent more tilty in curve of saturation
The EQ PG is the most conservative of the 3 in compression and distortion/eq curve
All that to say that beware of those carrecteristics , use them when needed because when so they will do wonder , if you need clean of clean just go waves , if you need api curves and preamps impact , you re in the right place just be aware of the impact !!