New Cluth, Gear changes are weird

Recently my clutch fell to bits, so i got a new one.
 
Prior to clutch failure tho, my car was running like a champ, smooth shifts and all.
 
so it was put into a shop got the clutch replaced and they also changed the gear oil in one go (not sure if necessary)
(car has original E54-692 No LSD Tranny)
Anyway they replaced the oil with Penrite FS ATF and holy crap are the gear changes ****, i'm not sure if its the new clutch or the oil they put in but after 3 minutes of warming up its like a motorbike slapping into first (cold shifts seems ok). Every oil manufacturer castrol, penrite, nulon, valvoline is saying i should use ATF but the internet (you guys) says i should be using 75-90.
 
So i think i got two options try and order online some redline MT-90 or some royal purple syncromax or max gear? not sure which one.
OR is it ok to put 75w85 gl4 in there? like the nulon or penrite stuff? Those two are just down the road.
 
Help guys i feel like i'm doing damage.