That pipe u-turn wont hurt a thing, generally these short exhaust systems are difficult to tune due to being very short and little space to work with. Tuning for torque is one pipe design and tuning for top rpm HP is another design. This is why Yamaha has designed the EXUP system. In my engine tuning experience, I'm guessing by design this pipe will provide good torque in the low to mid range while flowing fine on top.
More times than not, I see an aftermarket pipe obliterate low end torque while only gaining a slight HP increase. Seldom am I impressed with the performance of an aftermarket pipe.
As far as cooling, I've had to add coolers to every Yamaha I have owned except the old Phazer, Lol. Those warm up riding days that go just above 32 degrees in Mich and dip back below freezing before I make it back to the truck cause overheating. Then those days in Minn when it's just too cold to ride and everything is frozen like a rock, you wouldn't believe they overheat at -40, but they do.