I purchased one of these beauties when they first hit the market. SKS Ray was the first person to try it out at one of the MFG shoots. He ordered one within the week. As to being heavy remember this was a full auto weapon. It also had a much shorter barrel. In the day of their manufacturing composite material was not an option. It was built to withstand extreme cold temperatures and was attributed to inflicting massive causalities in the Winter War. It was considered one of the finest built weapons of its time for simplicity and barrel change out.
The trigger is a bit stiff but its a battle rifle not a 10/22. I love mine and some 000 steel wool and Kroil oil on the finish with a result in an almost original blue look.
As with all rifles I dissembled mine upon arrival and cleaned it. After 200 rounds the trigger freed up and the action worked great. I shot all types of ammo. Even Wolf functioned great.
I would not suggest reducing the spring tension/ weight. The rifle will not function if you do. There is an article somewhere on the web, I cant find it now, it talks about the need for the tension strength of the spring. I also suggest buying a parts kit as Ray stated. If something does break you wont find parts at your local gun shop that's for sure.
I guess I lucked out as far as the drum goes. Mine functioned without any issues. As to mags, they are selling for as low as $11 so hunt around.
For all who have purchased one, ENJOY, for all of those folks who have yet to purchase one.....ya don't know what you are missing