Thanks all, I'll definitely have to give Portra 400 a try, maybe later if I get the chance I'll try Reala too.
thegman, when you say if you overexpose it, do you mean actually shoot the film like its an ISO 100 film, and then develop it as such, or just overexpose the film and then develop it as a ISO 400 film? Sorry, still a student and learning my way around film.
Just overexpose and develop as ISO 400. So basically, all your photos will be 2 stops over exposed, which on most C41 films is fine, you get more shadow detail and colours tend to fade just a bit.