http://www.airsoftcanada.com/showthr...&highlight=A17
And if you were verified. I'd link you to a thread on this very subject where a user named Conflict wanted to 'Upgrade' his A17 walmart special and ended up getting the same answer.
You're not going to get any answers in different, the guns a peice of shit. Its not worth it, and to be quite frank with you.
This is
Airsoft Canada. Not Clearsoft Canada.
And sure, if this gun is TM compatable you're free to find out. You can easily help yourself by going to Google.com, search 'Drop in Gearbox for M4', buy one, stick it in your gun and whammo. Done deal, you don't need forum help to do this. Perhaps a bit of effort would help you. And if that gearbox doesn't happen to work, perhaps you could use a bit of thinking power to realize that these plastic guns aren't made for actual AEG parts. I doubt the thing will even get proper compression.