Bust out your tape measure. If it's small enough to fit... it'll fit.
I can tell you now - the 3.0 is a BAD powerplant. And, since there's no kit to fit the 3.0 in - you better be comfortable fabing your own parts / motormounts / transmission mounts. You'll also have to figure out a way to fit the 3.0 tranny in, or mate the 3.0 to the sami trans... etc.
Basically - if you want to stuff a "free" (I use quotes 'cause it's going to end up costing you a lot to stuff it in anyway) motor in your sami bad enough - there's always a way. You just have to have the tools and knowledge on how to do it.
I guess it's one of those "If you have to ask, you probably don't have enough knowledge to do it on your own, so I wouldn't advise it." kind of things.
Stick with the 1.6L conversion - it's going to cost you a lot less money and time in the long run.