Update:
The Clutch kit and Flywheel were replaced.
I'm not gonna push it hard for about 1000 miles to let it get broken-in properly, but looks like the issue is resolved. Maybe it's too soon to judge, but as far as I feel, throttle looks more responsive. Let's see what's going on!
Here are the part numbers for people are interested to know
Twin mass Flywheel : 21-21-2-283-824
Dual clutch:28-40-7-842-841
Clutch cover:28-40-7-842-842
Snap ring:28-40-7-842-843
O-ring:28-40-7-842-844
Shaft seal: 28-40-7-842-845
Isa screw:11-22-7-805-708
BMW DCTF-1:83-22-0-440-214