an M50 has an 819 CC engine. Plenty to haul you around with. I believe it is rated for about 500 lbs total including accessories, rider and passenger. One thing you DO have to watch out for with the Suzuki lines is the height of the passenger pegs. I know on the C series (formerly Volusia), the pegs are so high you passenger better not be much over 5' tall or they will cramp up on long hauls.
I ride the C50T and have no problem keeping pace with the 1500 cc Harleys I ride with.