Mick put the chassis on pole at robopong yamaha Senior and the chassis is completely compatible with any motor. The ikart with all its features can be set up very “free” which works well in low Hp classes as well as set up beautifully for Tag. We (Force.One Motorsports) have been using the chassis since last august and it has shown phenomenal pace in both tag senior and junior. We also have a customer using it in mini max with great success. I personally have been running in the GearUp F-series F125 class which is Leopard Heavy at 380lbs as well as tag senior. The chassis is fine with the weight. A little known fact is iKart has 2 frame Thicknesses. the Standard wall and “thick” tube which is a special order. I personally have been using the thick and it handles close the same as standard other than being slightly stiffer, but with the weight i have and being a higher center of gravity, it just plain works. iKarts with all the adjustment is one of the most versatile karts on the market right now.