If you going for the G36 route, Try to get your hands on a CA.
You might have to pay a little more up front then the cansoft brands, but their bodies are awesome,
Plus, internals can be imported without hassle, bodies can't, if you decide you don't like the body on your SRC or KWA, your kinda stuck with it. CA bodies are a really nice nylon fiber, unlike most other brands.
L85s are cool, really unique, and ISC is pretty easily available through Mach1. Theres a really extensive review of the internals of the ICS here somewhere, I'll see if i can dig it up, but it goes through each mechbox components and confirms what works with what (for replacement/upgrade parts)
A few other brands make L85s, but I have no experience with them. I would probably just stick with ISC.
EDIT:
heres that review of the ISC, check it out,
http://www.airsoftcanada.com/showthr...hlight=ICS+L85