Well basically, i have found that if you are in between 200 and 230 pounds and have serious skill like Randy Couture you can basically fight anybody in any weight class, look at the Randy Couture Tim Sylvia fight tim sylvia weighed like 300 pounds and had a 12 inch reach advantage and Randy absolutely butchered him and he only weighed like 230 he also fought Brock at this weight and held his own.
that is the primary reason why i want to go up to that kind of weight,
if you think someone at 155 can hang with someone at 205 or higher in an mma match or street fight you are in for a rude awakening, hence they have weight classes, but there are no weight classes on the street are there?