32 hours - on second playthrough. (i had no work to do this weekend 
)
I think i was at about 22/23 hours for the first 120 stars.
I have 32 stars with Luigi i think.... I didn't think he jumps any farther than Mario though, nor does he seem to run faster (he is very slippery though)
Also i was looking forward to saving Mario from the Haunted mansion...but it was a Luigi Twin....I think points should be docked from gamerankings! 
@Rol. Do you know if you just leave Luigi (the second one) in the first place he "helps" to find a star, can you find the others by yourself?
I have just realised that with slippery Luigi, playing 'luigis purple coins' is going to be immensly frustrating...It was platforming heaven for Mario but I imagine i will be cursing a lot when i get there.
