Clunk noise from driveshaft / diff ?

[miker1017]

I just installed a new guibo, center support bearing, welded diff. I now have this clunk noise coming from under the car. Not sure why it is happening. The input shaft on the diff I welded has about 1 mm of play but I heard thats normal. Someone please confirm. In the video I hold the brake while letting out the clutch to exaggerate the noise for the video but the same noise is happening when driving just more quiet and less violent. Also I must mention the car is a 325e with an m20b25 swapped by the PO. Supposedly the 325es came with a dual mass fly wheel and the 325i's did not. Could this noise be the dual mass? Also if I torqued a driveshaft bolt while in gear is it possible I damaged the internals of the transmission? I'm gonna get the car back in the air tomorrow, but any input is much appreciated

https://imgur.com/a/bH1lW9F

[Lugnuts]

Diff carrier bushing? The diff / rear subframe will twist from engine torque (read this somewhere...unsure if it's accurate given the diff is bolted to the subframe with 4 large M12 bolts...). If the bushing is shot, you'll get a clunk.

[digger]

input shaft has 1mm of play in which direction? thats not normal regardless