Deanyel is right when he says that it depends on your driving. But if most of your driving is at constant speeds of above 50 mph (80kph), then the 2.3 5-speed will likely yeild a higher efficiency. Because the final gearing in the highest gear is generally higher in a 5-speed than in a 4-speed.

Jeff Pierce

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Jeff Pierce

Current Vehicles:
'92 Mercedes 190E/2.3 (247K miles/my daily driver)
'93 Volvo 940 Turbo Wagon (263K miles/a family truckster with spunk)
'99 Kawasaki Concours
Gravely 8120
Previous Vehicles:
'85 Jeep CJ-7 w/ Fisher plow (226K miles)'93 Volvo 940 Turbo Wagon
'53 Willys-Overland Pickup
'85 Honda 750F Interceptor
'93 Nissan Quest
'89 Toyota Camry Wagon
'89 Dodge Raider
'81 Honda CB 750F Super Sport
'88 Toyota Celica
'95 Toyota Tacoma
'74 Honda CB 550F