found it on my own in the K4. Engine is so powerfull, you almost have to be idling to keep from starting to feel compression at times. Since trim just moves the controll surfaces, you'll have a larger elevator imput with trim than without it.
I guess a good way to put it is that trim helps get rid of some of that 'heavy' feeling in the controlls.
Ardy, I'm not saying trim helps you maintain your corner velocity, I'm just saying that once you go past it, and get into the range of mild compression, trim will take away some of the 'heavy' feeling to the controlls.