I have done mine in the touring, I am fairly handy but this is the worst job i have everundertaken...
you need to take it out - or even better buy another to work on so you can just swap them over...petrol removes the 'STAINING' orange foam.
It's recognised that spray glue comes off over time and heat, use a tub of contact adhesive, i bought mine from ebay - you want rapid set (10mins) as you have to glue a bit, stretch a bit, glue a bit etc.
The other guides all mention stretch, but i ignored it and bought nusuede! - its a fucking nightmare, you MUST have strecth in your fabric - the more the better. if you can get it done for £200 then do it, it took me hours and it doesnt look that great.
Seriously good luck mate - if you do buy another headlining to trim remember it must have the same check control and electric/manual sunnroof.

job good luck