What are the parts that most commonly fail in a Daewoo K2 or DR200?
More specifically, what are the hard to get  parts that fail?

I bought a used one which had a failed trigger pin, however, the trigger group is similar to the AR for the most part and I just replaced it with an AR pin and the hammer spring was weak so I replaced that with an AR spring as well, no problems since.

A couple spare firing pins would definitely be handy to have.  Check out this yahoo group-

groups.yahoo.com/group/DR200/

A while back someone was making spare bolts and firing pins.

I have a K2, great rifle. AR mags, FAL gas system and folding stock knuckle, AK piston setup, very light.

S.O.

does any one know where to get a gas regulator plug for a dr200???????
my friend didn't put it on right and now it's gone

Though it is possible to have a failure on any mechanical device, do not fret because Daewoo's are well built and super tough, they have no weak spots I am aware of...I have had a D-200 as my truck gun, for over 10 years now and have totially abused it, thousands of rounds through it and it remains 100% reliable with no failure whatsoever...not only that but it is phenominally accurate. The D-200 is one of the most underrated rifles out there, in my humble opinion. The Korean Army beats the hell out of them in horrible weather with almost complete reliability, and remember, the Koreans developed them in the first place, to be a more reliable alternative to the M-16 in the cold, hence the reliable FAL gas system.  

Quoted: does any one know where to get a gas regulator plug for a dr200??????? my friend didn't put it on right and now it's gone

Someone was selling a home-built one on Gunbroker recently.  Try there.

thx from the checking i did i am not alone in the needing a plug problem, lol