It costs so much more because you suck and HK hates you. I swear, HK is like the Dominatrix from the Beerfest movie and there ain't no safe word.
ANY aftermarket mods will reduce the value to most potential buyers. The "Cult of HK" is spreading. IGF has a blurb on their website, basically saying they make decent high quality HK clones from parts kits. If you are the type who has built a shrine in your den for the genuine HK91 you bought in NIB condition (and never fired) and send a Christmas Card every year to the worker who did the final inspection and packing of your rifle, neither you nor IGF will be happy if you send your kit to him.
ANY aftermarket mods will reduce the value to most potential buyers. The "Cult of HK" is spreading. IGF has a blurb on their website, basically saying they make decent high quality HK clones from parts kits. If you are the type who has built a shrine in your den for the genuine HK91 you bought in NIB condition (and never fired) and send a Christmas Card every year to the worker who did the final inspection and packing of your rifle, neither you nor IGF will be happy if you send your kit to him.