I'm aware of speed limits and the recommended 130 km/h speed limit. Admittedly, other than maybe one small push at reaching maximum speed safely, I'll probably stick with speeds in the 120-130 km/h range. I've driven at similar speeds here in the US, so I'd feel comfortable and at ease while driving at those speeds, and it's better for fuel consumption when compared to even higher speeds. Regardless, it's still nice to drive at those speeds in areas where it's legal to do so, something that isn't common in region of the US.
Regarding car rental: try Sixt
I'll check out their prices and give them a try.