When selecting a 90 Hp tractor, focus on the engine displacement and torque reserve, as these determine the machine's ability to handle heavy loads. Ensure the tractor features a 4-cylinder turbocharged engine for optimal fuel efficiency and power. Check the transmission system; a 12F+12R shuttle shift or synchromesh gearbox is preferred for smooth operation. Additionally, verify the hydraulic lifting capacity (typically ≥15 kN) and the PTO (Power Take-Off) speed, usually dual-speed 540/1000 rpm, to ensure compatibility with various implements like plows or harvesters.