[tunabreath]

Sorry, I wasn't entirely sure where to put this thread. Upgrades didn't seem right as I'm mostly inquiring about stock guns, Guns seems inappropriate since I'm talking about a component rather a specific model.

In any event, this is probably a pretty noobish question. I'm only asking because I haven't gotten any field experience yet as to verify the facts myself. Each article and review I read generally point to the conclusion that long barrel = outdoor/woodland, short barrel = CQC/indoor but differ on the specifics. While I understand the practical size limitations in the context of CQC, the performance aspect is what concerns me.
Typically, what I have read tells me either a longer barrel makes a gun more accurate, a longer barrel makes a gun shoot harder (fps), or both. Many sources afirm one and deny the other, while others apply oppositely.
On top of this, I find that it is generally accepted that all stock TM AEGs perform more or less identically, regardless of model (and consequently, barrel length). In discussion however, long guns are still regarded as superior in range and accuracy. Is this only in reference to upgraded capability?
Lastly, the upcoming MP7 seems interesting. I only browsed TM's site (can't read japanese after all) but more observant people on Arnies stated that it fires at 90 m/s, so ~295 fps. Now, if this is with .20g and not .12g BBs, that exceeds the stated stock performance of many of TMs previous long arm AEGs, in a miniscule package no less.

Exactly how much effect does barrel length have, especially in a stock gun?