Key difference - Sony have confirmed the PSP Go. The PS3 Slim doesn't exist yet and the photos that were circulated didn't originate from Sony.
So I'd love to know where the news that this non-existant console is going on sale within 4 months has come from.
Some guy claimed he did it however the cover for the PS3 Slim was exactly the same as PSP Go. No one knew about the Go box until a couple weeks ago so yeah the PS3 Slim is coming. On top of that 2 'moles' said it would be releasing the Slim around September time and they have been correct so many times before.
In conclusion the PS3 Slim is releasing this year and I'm sure Yamauchi will be twiddling his thumbs until he gets the green light for a release date. GT Portable is being treated as a system seller so that should give everyone an idea about what Sony wants GT5 to accomplish in terms of sales.