Re: Which kit?
Just because the kit says "grubee" on it doesn't always (or necessarily) make it a better kit. Sometimes, a kit will have better components like the throttle, or the muffler. However, the basic chinese bicycle engine kit is somewhat of a crap shoot when it comes to quality control.
Better to learn a bit about them, and buy one for a good price. You'll be tweaking and making mods and adjustments as you go no matter what you buy.
P.S., there are those that will tell you the kits by bikeberry, boy go fast, lucky early bird, ect. are somehow worse than others, and vice versa.