how tough: engine swap - 91 3800 into a 92 Lumina

I have a 91 Buick Lesabre.
awesome motor, uses very little oil, no leaks, ect.
The body is rusted to shit. The interior is crap. The windows barely roll down.

I can buy a 92 Lumina
Great shape, Euro package
The motor is blown.

Anyone know if these cars use the same transmission?
How tough is a 3800 engine swap into a 92 Lumina?

Thanks

Subframe ,all the mounts, complete engine and pcm harness from a Regal with the same drivetrain, exhaust, everything is different.