You can get the 5speed tranny w/ VLSD from a Infiniti I30t or a canadian model maxima. Both of those are not real easy to find though. And if you talk to a junkyard who claims to have a LSD tranny, dont believe them. 99% of them will say yes when they don't.
All the turbo kit information is on my website
http://www.hlh0501.com/turbo.htm.
Maxima motor with tranny, I am not sure where you buy them together unless you are buying like a donor car. You can usually find a maxima motor (vq30de) for ~275 - 350$ , but what is wrong with yours? Mileage isn't such a big issue just run a compression test
Maxima tranny's, even non-lsd get a little more pricey though starting in the 600 range