lol its fine man, it's just some people HATE replicas and some people like them. It's not just with wheels, it's with every part another company replicates. It's the whole JDM ego thing, and who has the biggest internet ego. I gave you some information on them, I don't know what other kind of info you wanted.
17x7.5 +48 will be fine, but if you are gonna SLAM it you might have trouble with the suspension due to the high offset of the wheels. 17x7.5 +38 you will most likely not have that problem, but this is IF you are slammed or lowered a lot. As for the hub bore, I am not to familar with it, if you contact wheeldude (
WHEELDUDE.COM) then he can help you more and if you order from him then he will make sure it's going to fit your FG2.
With Rotas it's gonna be hard finding the exact specs you want. I doubt they will have 17x7.5, but they will more than likely have 17x7, and usually don't have the best offsets either. Other companies make TE37 look-a-likes too. Try searching MB weapons. They arn't exactly the same, but some people like them more.