I don't know about the FZ, but I have a 2001 Yamaha TTR 225 that was manufactured in Brazil, and that little sucker takes large amounts of abuse without any problems, so I think they have the quality control part figured out, I understand that they produce the 225 in a street legal version that is also very reliable.
Buy the FZ. It looks more modern. There are more aftermarket goodies for it. In my area naked bikes are not popular at all. There are more FZs than Zrxs and hornets. I own a ZRX. So I kinda pay attention to naked bikes (at least till I find a buyer for mine).
Screams escaped into void as the mind-scape of tortured dreams closed in on the Cretinous Crusader. Suddenly, he sees the pan-galactic, clockwork spiders crisscross the pavement of frozen mercury, tracing glorious parabolic arcs of poisonous sparks behind them, as they hang-off their plutonium, powered neurocycles, and race headlong into his cerebellum.
On the out-most periphery of his consciousness, our hero hears his name chanted by a multitude of fleshulous, sex-starved nemphoplasmahoes. "Steve Steve Steve," they cry out, begging for his manliness.
Unfortunately, thats when Steves alarm clock went off and he, once again, found himself waking up in a slimy pool, of the Wesson Oil that hed been using to pleasure himself with, the night before.
Having checked your Info, and seeing that you are a engineer living in Brazil, it's pretty obvious that you would have all the technical aspects covered.
And, seeing that you're interested in the FZ6, it looks like you're not looking for a full-on sportbike, and have a good bit of common sense.
If that's the case, I was wondering if you might just consider the Suzuki 650 V-Strom.
Having ridden the Strom, I have to say it's probably one of the best examples of a "Swiss Army Bike" out there, and makes lots of sense. Yes, it is a mite ugly, but it makes up for that. From what I've heard about South American roads and traffic conditions, the Strom's upright riding position, suspension and versitility might be what you're looking for.
Still, you're the engineer and know what you're looking for. Just something you might want to consider...Good Luck: Kevin