So for those of you who have put your beloved Masada off to the side because you realized the proprietary parts are broken and seemingly irreplaceable, take heart! I just received an order from Wii Tech, and got replacement parts for all the proprietary internals. This includes a high quality metal replacement for (1) the shitty plastic hop up, (2) the shitty plastic feeding tube inside the mag well, and (3) the not so good air nozzle. I must say that I am super impressed with the quality of the parts, the speed with which they got here, (only 1.5 weeks from Hong Kong) and the low price of 5 bucks for shipping! I just got everything installed, and it works like a charm! The metal hop up seems to be giving a better air seal than the previous one, also.
Here's a link to the company:
http://www.wiitech.com.hk/eshop/index.php?cPath=67
Simply look for the A&K parts, and enjoy! Everything fit like a charm. I coupled it all with a Lonex piston, and piston head, PDI w-hold bucking, and a Tb barrel, and it's shooting real pretty.
I hope this helps anyone that needs upgrades for their Masada, but couldn't find any. Cheers.