6n suspension top mounts

hi guys I've been doing some hight ajusting on my coilovers hight wise so my new wheels would fit :-) . but before i started to do this i drove the car to work thismorning. then on the passenger side front was cating badly on the arch. so i then ajusted the suspension. once i had done this i thought i wonder if it has ajustable dampering..... i then stumbled across that i never but then relised that were my top mounts are on the centre nut of the strut on one passenger side has about an 1.3mm of thread comming out of the nut but the drivers side has no thread comming out of the nut, its just sat flush with the nut .

was just wondering what difference will this make to my suspension / dampering and if i was to alter this what would happen??

much apresheated for any help or advice on this :-D

thanks Brandon