Sink & Bath plumbing

[deasonuk]

Previous late 90's house has had 40MM pipe running along in boxing that I'd quite like to remove in my bathroom refit if it's feasible and do a wall hung basin. 

 

Existing mains feed spurs off existing 22mm pipe directly up through the floorboards, I planned on spurring off this 22mm direct into the Stud wall. 

 

Waste outlet hole is 40mm to the soil stack. 

I plan on extending enough 40mm for the bath drainage and then for the sink basin I thought I'd be able to go 32mm from sink to 40mm and run this through the stud but reviewing a few posts it doesn't sound possible to put the pipe through Metal stud (Needing to drill for holes) and also will mean sound issues? (It will be 20/30mm Tileback to front. 

 

The fall is another challenge, the wall width is approximately 1500mm.

 

Am I right/wrong on this and does anyone have advice on this ?

 

Boxing would be possible but clutter this room big time so I'd really like to avoid this if I can sensibly and easily.