I feel your passion for the 2 cycle motor. Just an FYI, the times of the 18-20 HP Yamaha kart compared to the 15 HP world formula is a few 10th of a second. Now if you take my 43 HP shifter you can $$$triple$$$ the price and go 2-3 seconds faster.
See what's it like to drive a shifter EKN topic
Or my personal comments:
It is like driving the fire breathing dragon!
I also drive a World Formula and find it good for keeping sharp on the art of smooth driving. It is easy to overdrive the shifter and get caught up in the acceleration and braking ability of it. Slower is faster when driving.
Watch the guys at the front, they usually look like there out for a Sunday drive. Then look a the mid packers and back markers, They are the ones riding the dragons!
Keep two karts
I know we would all love to see more people enjoying karting with us, whatever class it might be. Also, is this SQ kart on par speed wise with the other TAG"S? If it is that is great. Low cost and competitive!
If not you have just fractured the karting community by adding another (run this and only this) class. There is the easy kart class already, and creating more classes tends to confuse the new guy getting in and creates smaller class sizes overall.
Hay, I hope you get 20 of your buddies to buy and race these karts! The more the merrier!