Heres a trick I stumbled across a few years ago that I've used a couple of times to get really rough heavy gritty sounding drums when working at a lower tempo. Not sure if anyone else has tried this but its really simple and works a treat providing you pick the right sort of drum hits. Pick your drum shots (kick, hat and snare - no other percussion needed) and compose a drum loop at double the tempo you are going to be working at. Bounce it down to audio and import back into the DAW. Change the project tempo back down to the correct speed and time stretch your imported drum loop to match the new slower tempo. Now layer the original drum hits you used on top of your new timestretched break. Add any extra percussion elements you want and process as usual. As long as you mix the drum break well with the other one shots you should get really heavy thumping sounding drums. Cheers.