Thank you for the thorough reply!
Well I have been pretty dead set on GBBRs as I would like to own one for the joy of having one and it would be a bonus if I could use it at club days (hoping I can downgrade most of them with different buffer springs to meet the clubs' FPS rule of 350 CQB/Outdoors).
One GBB I was really interested in was the King Arms M4:
http://shop.ehobbyasia.com/king-arms-co ... rifle.html as it also has the ability to be turned into an AEG by swapping out the internals. Also the KA gives you some neat stuff that let's you adjust the power of the rifle to lower or increase in the box which would be a nice bonus to downgrade to meet club FPS rules.
But then I read from different forums and reviews that G&P would be a better way to go for GBB so then I looked into this G&P M4:
http://shop.ehobbyasia.com/gandp-woc-x- ... 18528.html I haven't had much time to look into too many details about the G&P but from the little research I've done, they're reliable.
I haven't given too much time on AEGs as again, I am quite set on the idea of having a GBB even though it can be time/money consuming to tune/fix/what-have-you. But my biggest gripe for going GBB instead of AEG is that AEGs are not that much cheaper than some of the GBB out there.
Well my biggest requirements on a gun would be as follows:
-Full Metal build (Mainly Upper/Lower Reciever) - Internals being metal/aluminium is preferred (Yes, this pretty much throws Tokyo Marui out the window on the basis they are plastic builds with aluminum plating at best)
-Has a rail system (like the ones on the two guns I linked earlier)
-Realistic functions (e.g. Removeable hand rail(if there is one), Working bolt catch, realistic field strip, some other realistic features that suddenly escapes my mind)
-MUST BE AN M4!!!! with adjustable stock. (NO FIXED STOCK and preferably not one of those folding stocks either)
-Preferred long barrel 13"-14" ish
-Preferably a GBB but could be AEG depending on cost/build materials/quality
-Did I mention, it must be an M4?
Going back to the two guns I linked, the KA M4 and the G&P M4 WOC-X, those two guns are the ones that I would be getting if there was no big flaws with them. As of now, I am leaning more towards the G&P for the better internals (or so I've heard) and G&P being a more reliable company (or so I've heard). The reason why I am looking mainly at the KA and G&P is that they seem to be the few companies with a lot of inter-usable parts without the bank breaking price tags. I originally looked at ICS but apparently ICS can only use ICS parts mostly due to the nature of their build or something rather.
Couple more question before I sign off for the night
- If I were to have a GBBR within club FPS regs, would I be in any ways disadvantaged or disliked for having a GBB? (As in will a GBB more likely to cause injury or make too much noise which may annoy team members, kind of deal) or does it really not matter which gun is used in the club so long as it meets the club regs?
- I also read on the club documents or something that Hi-Cap magazines are a no-no and magazines with 100rnd capacity was the maximum. (I realize this won't be a problem for me if I do go GBB, but nice to know for future in case I do go AEG

Anyways, I really do want to check out the club so in the end, I want to get a gun that would best fit in the club atmosphere, even if it means getting an AEG over a GBB
Sorry for the really long read, but as you may have noticed, I have been researching flat out for the last couple weeks and my head is rattling with a bazillion questions that need answering or I'll end up losing sleep over it. And all the forums everywhere says the same thing, 'Go to your nearest club and let them deal with your insanity.' ... so here I am

Thanks again!