I was wondering if it is possible to swap in a 540, M5, or e36 M3 engine into my e34 euro 520i. And also what other componants would need to be swapped.

Seeing that you've got a 92 M50 E34 it probably has a non vanos which means your only bet would be to swap in a 2.5 M50 or get S50 rods, pistons and crank slap it in there. machine work would obviously be required. Actually you could swap in any OBD1 24V BMW six in there you just need to swap a Vanos computer/harness in as well. Hey how'd you get an E34 520 in NH.

Someone that was in the military, stationed in germany, shipped it to New England in the mid 90's then sold it to a dealership in my town, then I bought it from a guy who had bought it from the dealership. It had just under 100,000 kilometers~ 60,000 miles when I got it.

That makes your car so much cooler then, you definitely have to do something with it.

Dont hate on the 2L..
Turbokits for the M50B20 cost peanuts on ebay, and some work like a mutha!
Currently running 0,8bar of boost on mine with a lowcost haltec-type squirt, will make a thread about it here soon. Know someone who got 321(!!)hp on 1,2 bar in a E36 320i, still untouched engine

Im apparently not allowed to post any links or pics yet though.. Stoopid new member rules :P