After changing clutch + flywheel, all new + genuine parts,on my 05 stiuk, i have noticed a vibration at 3000rpm through the accelerator pedal area, more noticeable in 6th gear when slight throttle applied. will not make vibration when just free reving engine+ when i fitted clutch manual said to put 0 marks 120 degrees apart , could not find these marks at time ,so used paint marks instead' any ideas please

 

what does these marks mean?