ive just got back into mountain biking after 15 years , i bought a kona nunu and its has Shimano M445 Hydraulic Brake Levers front and rear , Shimano 160mm Rotor , the rear is fine but im running out of power on the front , can i buy a better more powerful front Caliper and bigger disk , i know it will need greater force on the lever but better stopping is more important to me than a really light lever , im 16.5 stone and the front even with maximum force isnt really that great , good but not great ….can i buy a caliper on its own and what do i get …
Forks are RockShox Dart 2 100mm w/Turnkey ive read that these are pretty poor forks but better than what i had 18 years ago and are still smooth ( 150 miles off road ..ok not even run in yet lol )
thanks for any advice

Yes you can buy a calliper on its own, but you might be better starting off by giving them a bleed and fitting a 180 rotor (you’ll need a five quid adapter and a new rotor).

If that still doesn’t word I’d say just buy a new front brake set (lever, hose, calliper). SLX are good.

*ninja edit, if you do decide to just buy a calliper, it has to be another shimano one to work with your existing lever.