Questions before buying

Don't know for sure if my answers can help you out. I have never read on or heard of the "Prius T Sprit" in the North America market.
I don't know about the "Protection Park" that you are saying neither. Do you mean the "Auto Parking" that is offered with the top trim level? If it is what you are talking about, it is a very complicated computer software control that, by aligning some yellow lines showing on the NAV screen on the parking space showing on the same screen, the car will move itself into the parking spot for you. I have tried it before I bought mine without it. If you know how to backup parking, it will be a total waste of money because you probably can do it 10 times faster than the computer do it for you. My advise, if you want to show off, buy it. If not, save it.
Your MPG question: I don't see any difference in my gas consumption when travelling on the highway at medium or high speed. The consumption stays about the same. The time it makes the difference is when I floor the pedal to pass someone. When cruising at a steady speed, the consumption doesn't change much at all. Of course, going uphill will use more and vice versa.

 

The protection pack is just some rear parking sensors (beep while in reverse) and a boot liner (at least is is for a T3). I don't think it is anything to do with auto park. Your dealer should be able to confirm this.

In my T3 I get about 45mpg motorway driving @80mph. If you come down to 65-70mph you can get 50mpg easily. For 40mph on dual carriageway it depends if you can do constant speed, or you are in start stop traffic. For constant speed I can get about 55mpg. For start-stop and commute in a 40mph area I can get 58mph. These are winter figures and I am expecting these to improve as we get into summer. I expect the Tspirit to be similar although it does have 17" wheels instead of the 15" on the T3 (unless you get a solar panel in which case the Tspirit gets 15" wheels).

 

Look at post #27 by Bob Wilson on this thread: http://priuschat.com/forums/gen-iii.../68100-60-70-mpg-really-not-sure-about-3.html

There is some good information on fuel mileage there.

 

Neil,

I respectfully disagree with Toyolover's claim that speed makes little difference in MPG.

My experience is that it does, though I'm not yet able to quantify it completely as to my car. The suggestion by Tumbleweed about reading bwilson's post is great--he has a chart of his experience of speed vs. mpg which "feels" right to me and many of us.

Based on my drives at 80 MPH, 45 MPG sounds just a bit high--I would say we get more like 43--though I probably haven't driven at that speed as much as johal.