I have heard the same from many people. I guess the first few CEN products that came out sucked. The newer cens are great, especially for the price.

Now that I reread this whole post at a decent hour (i usually don't get on my PC until about 1 AM), I don't see you mentioning anywhere that you have adjusted the set screw for the shift point...
If you look at the clutch, there are 2 screwholes and one goes straight in and one is on an angle. The one on an angle is for your shift point. If you loosen it off it will shift at lower RPMs. it could just be too tight. You can loosen it off without taking it out by turning the spurs until the hole in the second gear (front one) lines up with the angled hole in the clutch assmbly. Try loosening it off 1/2 turn at a time.
If you look in your owners manual, it will tell you somewhere in there what that set screw should be set at. I can't remember offhand.

I will be ripping into mine tonight so I can check on that clutch position for certain. Your pics are a bit blurry and hard to see.

Will post later.