If they are like the bc coil overs you need to screw the whole unit to avoid changing the spring tension.
If not as in the whole assembly can't turn, turn the locking collar to adjust the height either down or up i am guessing as not sure what they actually look like or familiar with b14 coil overs.
Just googled it and looks like it ain't like the bc's from the picture I saw. Rear height adjustment is done by the collar that goes into the rear Spring, and front will be screw collar up and down then bring up the second collar on the fronts once the collar that contacts the spring directly is set at the height you want to ensure it won't come lose.
