Whats the purpose? I know they put it there for a reason, just not sure what it is. My guess would be to keep it clean, and maybe some aerodynamics for high speed driving?

 

It's all about air flow and how to control it to optimize performance. As you said , aerodynamics.

 

You've got a car that easily reaches 155 mph. At that speed, you want to minimise any instability caused by bad airflow under the car. Also helps fuel economy, too.

 

It also has something to do with cooling efficiency, besides the aerodynamic advantages. At speeds, the space under the car is a high air-pressure zone. Such high pressure can actually impede airflow through the radiator, reducing cooling efficiency. By installing the undertray, they can reduce or eliminate such high pressure areas right behind the radiator.

 

My understanding is that it Also is for protection of the electrical/electronics

 

It is not unusal to find undertrays on newer model automobiles. More and more automobile manufacturers are adding undertrays on their cars. They serve several purposes and many as listed above. Aerodynamics, cooling, protection of electrical and mechanical parts.

 

Funny but every time I walk out into my garage to get in one of my cars I can see under the Jag which is on the lift. There is one connector that is exposed to everything that the car runs over. It is the one that goes to the e-differential . It's just secured to a bracket but it just stands out.

 

>My understanding is that it Also is for protection of the electrical/electronics

It also protects the plastic transmission pan on the ZF6HP26 transmission.

Run over something, puncture the plastic pan and you're walking home...
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Jaguar: Grace, Pace, and Space - Sir William Lyons