How big do Maine Coon cats get ?

the Guinness book says the largest is Leo a 35 lbs 48" long cat and he is not over weight. how would you like that to have him jump on you in the middle of the night. mine weighs about maybe 15 lbs. and about 36" long. i call him a runt. he was a rescue cat but i think he is full maine coon as he has all the characteristics of one. long body, cystitis, really long fur, plays fetch, curly tail, trills when he meows, uses his front paws like he has a thumb, uses his paws to get water then licks them, is fascinated by water