As said, if you want to do it you can. Just how much time and money you have.
That said one of my mates has a 1GGTE with a big single on it in a gemini, 6 inches cut out of the firewall... It is fast tho. Very fast. Another had a gemini with a rodeo 2.6L in it (4cyl), and that had a single turbo set up, then a twin, then back to a single. Both those 2 were tidy. Only the 1g was legal tho.
I've seen a few 1GGTEs in corollas as well, although they do go in to coronas a bit easier apparently. All pretty rough.
And I have seen a 1jzgte in a 73/4 celica or something. Kinda tidy, just kept breaking stuff due to how it was mounted etc. As far as I remember they couldnt really come up with a better way, so it just keeps breaking stuff.
All very tight fits, I dont know how you would go with an rb30det/t. I just think the lenght and hight might be too much to fit it all in.
If you just want to go fast, go the 1G, they are a cheap and very tough motor.