Is it from cold or all the time ?
Could be one of many things but ad Clive advised me have a look atvthe clutch fluid in the slave and if it's haggard pull it and pop some fresh stuff in see how it goes, if it's noticable may be worth doing a full bleed,
Also could be down to worn engine mounts but yours is quite young so shouldn't be an issue, some good upgrades are group n pitch mount & gearbox mount & carrier bushes as the oem ones are a bit weak
Oe on lef, sti right
Oe gearbox mount & crossmember bushes
Sti/group n mount, less holes &stronger rubber