At the top of Tiffin's lineup, the Zephyr 45 PZ is built around a Cummins X15 engine producing 605 horsepower and 1,950 lb-ft of torque, backed by an Allison 4000 MH six-speed transmission and a steerable tag axle that makes a 45-foot coach genuinely manageable on the road. Ride quality gets serious attention here, with ZF independent front suspension, V-Ride air ride in the rear, and custom-tuned Koni shocks working together. Inside, Spyder touchscreen controls appear throughout the coach, from the cockpit to the bedroom overhead cabinets, managing the hydronic heating, lighting, and systems in a way that feels more like a connected home than a traditional motorhome. The Valid air leveling system with hydraulic jacks, a 12.5-kilowatt Onan diesel generator on a powered slide tray, and optional lithium house batteries round out an electrical and chassis package built for full-time or long-haul use.