Never saw an aftermarket mechbox for AEPs... just to clarify, was it a TM MP7 or one of the clones? Cuz if the mechbox will break from the upgraded spring, it may be a warning for others.
Anyway, for a replacement... not 100% sure it's identical (nor how good it actually is), but you could look into the clearsoft clone MP7s which are supposed to be Marui compatible (buyairsoft.ca has em for like $175 ). You'll get an extra battery and mag in the process, which might help make the replacement a bit less pricey.
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