g60 with a red line of 6000 wont last long if its spinning to make more than 1.2/1.3 bar.-..for that red line i would go turbo.
In my case the injection pump was the biggest limitation for max. RPM. Giles once said he has some ideas to make fueling work at 6k-7k RPM though. Definitely talk to him.
I'd say your AAZ rods are the weak point. Just using stock ALH rods would be strong enough, shotpeened even better. At 6000 rpm's, the bottom end is not what I would be worrying about, it'd be the injection pump. Brendan