I was also wondering if these inner sunroof seal's can be replaced & if so for how much?
What I have done @ the moment is remove the original & soaked it in hot soapy water for 10 min's or so to allow the rubber & the gunk & grime to soften, then using an old toothbrush & nailbrush cleaned it throughly!
Once this was achieved I soaked it further in fresh, clean hot water for quite a while!
My aim was that the hot water would then help the rubber to expand/return as best it can to it's original shape!
(After all in this country it does spend 99.9% of it's time compressed by the glass!)
After a long soak I dried it off & left it to dry further while I used the toothbrush and the vacuum cleaner to clean the sunroof 'groove' ready for it's return!
Upon re-installing it I left the sunroof open inorder to give the seal a further chance to 'set' the shape it had returned to!
Before turning in for the night I closed the roof & I have to say it has made a difference... how long it will now last... God Know's!
Hope This is Of any use,