I found this on the HPI site and tried it on my MTX3:
To check tweak (you should check between each race):
A) Hobby Knife Method: Set the car on a flat, level surface. Using a hobby knife, lift one end of the car at the center point. Watch closely which tire lifts off the surface first. If both tires lift off at the same time, that end of the car is not tweaked. If one tire lifts off before the other, adjust the tweak (see below), turn the car around and check the other end. Adjusting the tweak using the "hobby knife method" must be done by adjusting shock length. An easier way to adjust tweak is with a device like the MIP Tweak Station (see below).
My front and rear has tweak. Now to adjust, stupid me started to play around with the droop screws... go figure, i thought it would balance things out. Well it did, but is this the best way of doing fixing tweak, or am I better off extending the shocks of the wheel that lifts first???
What do you guys think? I tried measuring the shocks and they are all the same length, i think the load of the car is not centered so that is why its tweaked... any thoughts?