Shake:
I was told when I bought my parts that I could send it to HK for $50 and they would do the swap for free, or I could buy the parts from a local HK armorer and either pay them or do it myself.
Yes. I did buy my parts at a local dealer. I have two dealers there that can buy the parts, but only one who is an HK armorer. My understanding is, if the HK armorer puts them in and something goes south, you can send it to HK and they will fix it for free. If you do it yourself or have the non-HK armorer gun shop put them in, you foot the bill if its screwey.
That being said... If you have taken your hammer assembly apart before (there is only a loose pin holding it all together) then this is an EASY swap to DIY. If you arent comfoprtable, find an HK armorer and pay him the $25 like I did the first time. Remember to request your original parts back so you can swap it out later.
Now, the parts I got were for the right-handed, no safety version. Still has the decocker. that $50 was retail, so I have no idea if that price quoted you by HK was wholesale, could be. Since I paid to have mine installed (before I took apart the hammer assembly), I paid $50+tax +$25 install.
Hope this helps!
JT