Are the high performance kimpex pistons any good?

My 2013 Summit X is giving me a hell of a time right now, with a recent laundry list of oddities. Some of which I think are related to one another. Check it out . . . REALLY hard to pull start. By hard, I mean physically it's really hard to pull. Starts right up no problem if you can pull hard...

So i have a 96 summit 500 and i just bought it not running. Previous owner said intermittent spark. Cleaned carbs really good replaced both main jets. New fuel lines. And i relocated fuel pump onto side of airbox for easier acess. New plugs. 125 psi and 130 psi of compression. Hac is...