Ed_Boysun
Guest
Rotary capacity = HP You are going to pay 10% more for 20% more HP and thus capacity. Sounds like a no-brainer. I've not looked too closely at the 5 series yet, but I would guess that the cooling system will be larger on the 75, in order to accomodate the larger engine. If you are working in hot temps, that can sometimes be an advantage also.