Site limits are set by energy/power. 328fps with a .2bb is 1 Joule
325fps with a .43 BB is 2.15J, way over the limit for safe automatic fire
(that's heading for the 2.32J power of a 500fps .2g bolt action!)
ouch...i had no idea it was that powerful. So engagement ranges are key then, or is using it out of the question?
It will depend on the site... but there almost certainly will be a minimum engagement distance set for your use.
That's if they'll let you use it at all!
Doh.... 
If the fps you have given is correct then yes, it's pretty much unskirmishable.
Best to get it chrono'd! With a .34g BB the max fps will need to be 293fps, with .43g the max fps will be 260fps
My Blowback M1 Garand was doign 240fps, and i was using .43s, so luckily I could use it, that was on green gas though, no idea of how the Carbine performs.
Redwolf airsoft states its about 250fps using 8mm BBs and HFC134a. Which is alot better.
That depends on the weight of the 8mm bbs.
Also you may find that HFC134a won't work in the winter... its a damn weak gas.
Well im guessing they are the standard size .34g 8mm bb's. Yeah the weaker gas isn't great at all in the winter.
RE: the M1A1 Carbine (with the folding stock) - is it possible to fit a mag pouch on the metal arm of the stock? Does it still lock down against the stock?
Show me a man who will jump out of an airplane, and I'll show you a man who will fight!
General James M. Gavin
CRY HAVOC AND LET LOOSE THE DOGS OF WAR
No. They fall off.
Plus if it did fit..The swing arm wouldn't fold flat.
Any new information as to where to get an M1A1 stock?
SOF have them back in - for £150! 
When I want your opinion - I'll tell you what it is!