Somebody voted "yes" and it wasnt me. I'm curious to know the reason why somebody voted "yes"?
Personally, I think it sounds like a cool project. To buy a cheap GBBR and fixing it up with aftermarket parts. On top of that I'll still eventually get the KJW, just not as soon.
The problem really, is the cost to benefit ratio. If the AGM was $100 like in the States and Hong Kong, I might have done it without hesitation. In Canada, a used AGM is in the $350 range. Spending about $200 will get me a new KJW M4A1.
Aside from that there are no local airsoft stores that sell aftermarket parts. Meaning all the parts needed will have to be shipped to me. Which ruins the cost to benefit ratio in another way.
In the end, I think it would have been a cool project if the cost to benefit ratio is there. Given that airsoft stores are not common and airsoft guns are 2to 2.5 times the actual market value. Its probably not worth it.