I would really go for the upgraded G36 however at the same time you'd kind of need to know the seller as a good guy. Ask a lot of questions and stuff about the product, condition how much it's been used, any problems, etc.
It's really your choice but you probably get a better deal buying one thats been used and/or upgraded.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE