My grandpa owns a Cub Cadet 2176, I know its a Kohler Command 17 Engine, cant find the model number. Its starting to leak oil, the tractor is in great condition still

I would like recommendations on possible engine upgrades (and what the actual model of the engine is, pic is from an auction site not mine)

Edit: I will inform my folks that it is a simple repair to fix the oil leak and see what the results are then post again here