How would you build an Ultimate Towing Machine (E70)?

[bluetec]

Originally Posted by RickM5X3

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The 35d was omitted as I need something that is a fairly decent substitute for my old M5 when not hooked to a trailer..

I wouldn't rule out the diesel so quickly. Compare the HP/TQ curves carefully. Maximum torque on the diesel is available almost off idle. The X5d is a workhorse, and when you are not hooked up trailer it is still very respectable. The twin turbo setup is amenable to tuning as well, so you have some room to grow once you've broken it in. Diesels love to work hard, hot and are built hella stout. Disclaimer: Admittedly I am biased, but I have owned and driven diesel products all over the world. Some I did not tow with, but even the smaller engines outperformed their petrol counterparts, and... a diesel is made for pulling. It is not easy settling on a vehicle that will intermittently be used for towing. Consider test driving a diesel, *knowing without question* it will be the ultimate towing machine. Question is whether you will love driving it every day. Best regards.