Best way to compare is look up the stack and reach of your current bike, add your spacer height and bar rise to the stack height, and add your stem length to the reach. If your bike feels exactly right now in terms of fit then your new bike needs to have no more stack height (remember you can run the stem slammed and flat bars) than the current total stack (inc spacers and bar rise); and with a 30mm stem added to the reach the total be no more than your current total reach (inc stem).
The rest doesn’t really matter with a bike that’s mostly about going downhill. Definitely run 165mm (or shorter!) cranks – I’m on 170s on my full-sus with 33″ legs and I swear I pedal better than on the 175s on my hardtail.