It will be very good when the total vehicle weight is down to that (550kg).Paying for it requires just a little less that weight in gold I'll bet.
I guess that if anyone asked for all the above specs - performance, distance, etc etc, we would always come up with what we see.
In that respect a credible effort. A niggling thought says this will indeed be a sought after exhibit.

Maybe I'm dense here (and I'm sure someone will correct me!) but why do companies expend all these resources on an all-electric vehicle instead of doing some kind of PHEV? I would be interesting to see what challenges are needed to integrate a small engine in such a system.

Size the engine to the average power needs for the vehicle at cruising speed (60-80 mph). What would that be, 50-70 hp? Weighing 400-500 pounds? If you did that, you could take out 75% of the batteries, the net result would be cheaper, lighter, longer range, nearly same impact on environment/resources usage.

I'm saying this because PHEVs will be difficult to perfect, so working examples are helpful, whereas this is something that will never be produced in significant numbers, maybe not more than 1.

I disagree, Jim.
100+ mile range and overnight charging is suffecient for a large segment of car owner now, without the need for an onboard generator. Based on price estimates for the Chevy Volt compared to BEVs in the works from other manufacturers, the price difference may not be much. Less parts, less maintenance, and dropping battery prices should make them comparable to todays conventional vehichles with mass production.
I beleive that battery capacity and charging time will improve rapidly. A few years down the road, we will all be driving electric cars that trave 4-500 miles on a 10 minute charge, and the PHEV will go the way of the 8-track tape.

Placement of 5kg batteries for and aft or 'polar weight distribution' is not the ideal especially in a Porshe.
Ferrari, Masserati and some Porshe models go to much trouble placing as much of the mass as possible close to the the center of gravity as this promotes faster steering response.
Polar weight placement can give a feel of directional stability, but will certainly increase the tendancy for end swapping.

I got backpressure for complaining about battery and fuel tank placement on the roof of a fuel cell bus some months ago, but note a later article reported that the manufacturer? had downrated the speed limit to 55MPH owing to instability issues related to high center of gravity.
I was considering the air drag aspect and the stresses placed on he coachwork which on a vehicle in motion is already challenging structural engineering.

A response to my post suggested that convenience in servicing justified roof placement and one might be tempted to make a similar allowance in this instance.
I think it is important to always consider best practice learned over time and go the extra distance on principle.

@ arnold

Agree that in pictured Porsche (911) it is not ideal to place weight outside axles.
But I think that this way (batts at both ends, weight distribution closer to 50% than in 911 with rear engine) the electric version is more balanced.

As for the BAE Systems bus with batts and control module on roof (as of 6 October 2008, not "some months ago"):
Batt pack is rather small, 8kwh (see latest posts there), not too heavy.
My guess is they wanted to avoid significant structural modifications to the floor of the existing Orion bus. So they had to choose between quite hot engine compartment and the roof. The roof option was less bad.

If I recall properly, some CNG buses place their tanks on the roof, so it's not that uncommon.
City buses are usually slow moving.

@MG

Got all the Naysayer angles covered pal? LOL

Do you have any idea that the ICE you drive daily is about as energy efficient as an incandescent light bulb? From fuel tank to tires ALL gasoline-powered cars are approx 15% energy efficient. An EV like the Tesla uses 200wh/mi at a cost of $0.01 per mile. Any ICE powered car of comparable performance (absolutely no point comparing it to a Honda Civic... a Civic doesn't do 0-60 in 3.9 sec) costs more like $0.30 a mile and the difference is going out your radiator and exhaust system as useless heat! You read right 30x the cost per mile to drive an ICE.

And there's not much difference between the cost of a kw/hr be it liquid or electron, an ICE just wastes 85% of it.

Do some fact finding before you mouth off pal, otherwise you’re just displaying your ignorance.