I have done over 20 AVC-R installs and most had spiking issues... Most people make the mistake of using more than 2-3 feet of vac hose which causes a delay and can take the avc-r a bit to iron out. Other than that it never worked perfectlly over 12psi... Could not work it out.... Some cars it worked very well... Some it just didnt work at all....
Most have something to do with different spring compressions on different cars....
As for the settings. I now am using a gain of 10 in manualmode with boost set to 42... This gives me a perfect 10psi.... The gain basiclly sets how fast the car gets on boost... 0 will take days 100 will fry the tyres in seconds then the motor.... Any settings over 30 on a stock wastegate will cause spiking.... So gain is like a responce setting basiclly....
As for the extra readings yes you need the power meter to add on... It links either via another plug into the central cumputer or if sitting next to it, it will connect via IR...
The power meter will add all these extra features and more than the avc-r offers.
I will get a power id after i do a few more things. I see no need for it ATM....
To re-confirm i am now using the ID III in manual mode. Have not played with scrable as yet as im just happy to hit 10psi flat.... As for this mornings weather i had to turn it off and run stock boost as the roads were to wet... (Almost made a massive arse out of my self when i did a u-turn outside work)