Transporter T4 - which model best for towing?

[Laurence7]

Am looking at getting a Transporter T4 as a tow vehicle. I'd be towing a bike-engined race car, with spare wheels and equipment on a light-weight twin-axle trailer - all up weight of loaded trailer, about 1200kg.

There's a bewildering range of engine options on the Transporters Which one would be the best choice for high-speed towing, fuel economy, reliability, durability and drivability?

Are there any stand-out best models? ...or turkeys?