Just because a bike can handle a certain amount of weight doesn't mean that its suspension is ideal for that weight.
Precisely, The suspension is
NOT set up for that weight. To think that it is because the GVWR is set high, or it has passenger pegs is incorrect.
The bikes are undersprung for the factory, being set for a single rider weighing around 160 lbs. "Being able to carry more than 160" is not the same has being correct.
Correct suspension means sprung for your weight and the sag set.*
Ducvet will make your suspension work as best as your budget will allow, and you will be faster and more confident on the bike due to riding a more competent bike. Spend the money on suspension first engine second.
Truer words were never spoken. You'll be 'faster' everywhere without any changes to the engine, and you'll hardly notice that you've gained speed through corners, because confidence will be higher.
There's been another post about a rider going two up and wondering why the suspension was bottoming out around turns. Well this is obvious, the preload can be maxed out, and it still not be putting the bike within the appropriate working range for the suspension damping circuit. Its all about spring rates. RaceTech and many others have calculators for this kind of stuff online, make sure to use it accounting for your gear (weigh yourself with gear on, its heavier than you think.) Changing springs is not all that expensive and followed with adjusting preload to set sag correctly, will make a world of difference in the handling of the bike.
* In regards to your weight. Damping characteristics are resolved with shim stacks, valving, and oil combinations.